Moving On: The Expansion of the Family Network After Parents Separate



Separation and its immediate consequence, life with a lone parent, have received a great deal of attention in recent years. The rising proportion of parents and children experiencing this first, and most common, family transition has challenged those involved in social policy decision making. Less well documented is what will happen next, as mothers and fathers separately continue their conjugal and parental life courses-creating different family units as they enter new conjugal unions.

Equally unknown is how this process affects children's family experience. When a separated mother forms a new conjugal union, for example, an additional parent figure, and possibly stepsiblings, enter her child's family universe. The same goes for separated fathers. Subsequently, these new couples may decide to have a child together, expanding the child's family environment still further with the addition of half-siblings.

Transitions in the life of the custodial parent alter the composition of the child's residential family unit. In the non-resident parent's life, however, transitions may require just as much adaptation, as children see other children "taking their place" within this parent's household. These transitions may also generate new family responsibilities that change the relationship between children and their non-resident parent.

In addition, each family transition can have repercussions in other areas of the child's life. A parents' new union may involve moving to a new home, which may mean a change of schools and friends for the children. In the case of the non-custodial parent, it might involve a reorganization of visiting or less frequent contact. The additional family commitments may also prompt the non-resident parent to ask for a modification of the child support agreement.

Although society has acknowledged the growing importance of the stepfamilies that are created when the custodial parent enters a new union, there is little appreciation of how complex the family life course can become for children whose biological parents live apart. Instead, this complexity is often concealed in simple family distributions based on cross-sectional data and restricted to the residential family unit.[2] Understanding this complexity is essential for anybody involved in assessing the impact of family change on children, or in developing public policies that deal effectively with the consequences of this expansion of the child's family environment, such as the rights and responsibilities of stepparents.

In this section, we use longitudinal data from the first two cycles[3] of the NLSCY to explore the growth of children's family networks as parents go their separate ways. In the first step, we focus on the arrival (and departure) of new parent figures, as separated mothers and fathers form or dissolve new unions. In this step, we do the following:

  • evaluate the frequency and timing of mothers' and fathers' new unions, within Canada as a whole and for the different regions;
  • reconstruct the family life course experience of Canadian children, to illustrate how each conjugal transition in the life of separated mothers and fathers translates into family change for children by expanding and diversifying the family pathways Canadian children take through childhood;
  • show how the complexity of children's life courses is closely related to the different contexts within which they were born (whether that be outside a union, within marriage or within a common-law union); and
  • examine how these new unions expand children's sibling networks with the arrival of stepsiblings (children of the new parent figure) and how these unions create new family units within which half-siblings may be born (in both cases, these new siblings may or may not live in the same residential family unit).


A new union in a separated parent's life means a new "parent" figure, or stepparent, joining the child's family network.[4] Of the children whose biological parents lived apart before the child's birth or following separation, how many saw a new father or mother figure enter their family universe? What proportion had both an extra father and mother figure to adapt to? To answer these questions, we draw on information gathered in the family history and custody section of the NLSCY regarding parental separation and the new unions separated parents formed. Most of the following analyses are based on children interviewed at Cycle 2 (1996-97), when they were aged 0-13 years.

First, Figure 1.1 shows how common it is for children, who were born outside a union or whose parents separated at some point,[5] to see a new parent figure enter their family network when their mother or father forms a new union. Although they were, on average, only eight years old, more than half the children (52 percent) had acquired at least one extra parent figure in their family environment by 1996-97, and close to one child in five (18 percent) had gained two. Factoring in children for whom both parents entered new unions, one third (14% + 18%) of the children had seen an additional father figure enter their family network, and almost two fifths (20% + 18%) saw an additional mother figure.

Although high, these proportions do not give a true image of the extent of the phenomenon, as they combine the experience of children whose parents have been separated for different amounts of time-sometimes from the child's birth. Although a new parent figure may already be in the picture at the time of separation, and may even have acted as a catalyst for it, the expansion of the child's family universe occurs over time. In the next section, we use life table techniques to more precisely estimate the frequency and timing of separated parents' new unions.

Figure 1.1 Distribution of children aged 0-13 years in 1996-97, whose parents were living apart, according to whether new parental unions introduced extra parent figures into their family environment, NLSCY, Cycles 1 and 2

Frequency and timing of mothers' and fathers' new unions

At Cycles 1 and 2, when biological parents were living apart, responding parents were asked whether they, or the other parent, had formed a union with a different partner and, if so, when this new union occurred.

Mothers who had their child outside a union and had never lived with the child's father after birth, however, were often ignorant of the date of a new union created by the child's father. As this information is essential for calculating the table probabilities, children who had never lived with their father were excluded from the analysis. These tables apply, therefore, only to children who had lived with both parents from birth or at some point afterwards, and whose parents subsequently separated.

The tables are based, nonetheless, on a larger sample than that used in other analyses in this section (approximately 3700 children), as the life table method makes it possible to include incomplete histories in the calculations. As a result, the experiences of all children (with separated parents) interviewed at Cycle 1, whether or not they remained in the survey at Cycle 2, were included in the estimates.[6]

Figure 1.2a presents the proportion of children with separated parents whose mother or father had entered a union with a different partner and shows that the probability of forming a new union increases consistently as time passes after the separation. Fathers formed new relationships more rapidly than mothers: within three years of separation, one third of fathers and a quarter of mothers had already remarried or started living with someone other than the child's other parent. Ten years after their parents separated, over 63 percent of children had seen their mother set up home with a new partner, and 67 percent had seen their father do so.

From the child's point of view, the expansion of the family network is even more rapid than it appears when mothers and fathers are considered separately. Figure 1.2b presents similar probabilities, this time looking at the arrival of the first (solid line) and second (dotted line) new parent figure, irrespective of whether the mother or father created the union. The solid line shows the following:

  • Only two years after their parents separated, over one third of children already had at least one additional parent figure.
  • After five years, two thirds had an extra father or mother figure.
  • After 10 years, close to 9 out of 10 children with separated parents (87 percent) had seen one of these parents form a new union.

The likelihood that both parents will take a new partner changes more gradually; nonetheless, only five years after their parents separated, over one fifth of children had seen both a new mother and father figure enter their family environment, as did close to half of them (44 percent) after 10 years.

Regional similarities and differences

Figures 1.3a and 1.3b compare separated mothers and fathers in five Canadian regions, in terms of the frequency and timing of their entry into new unions during the first five years following separation. Mothers and fathers in Quebec formed new relationships more rapidly than in any other region of Canada. After only a year, for example, separated parents in Quebec were twice as likely to have entered a new union as were those in British Columbia. After five years, however, these regional differences among fathers were much less apparent; fathers in the Prairies, in particular, were as likely to enter a new union within five years as were those in Quebec. Among mothers, on the other hand, the gap widened over time; five years after separation, close to half of separated mothers in Quebec had formed a new union, but only one third of mothers in Ontario and Atlantic Canada had done so.

In all regions, fathers form unions more rapidly than do mothers. In Quebec, the gap between the sexes had more or less disappeared after five years; by this time, 47 percent of mothers and 49 percent of fathers had started a new union. Gender differences were most apparent in Atlantic Canada and in Ontario; in these regions, 45 percent of fathers entered new relationships within five years of separation, which was the case for only one third of mothers.

These regional disparities affect the speed at which children's family networks expand (see Figure 1.4). Within the first two years of their parents' separation, children in Quebec were much more likely to have an additional parent figure enter their family universe than was the case anywhere else in Canada. The gap shrank with time, as fathers in other regions caught up with those in Quebec.

Figure 1.4 Cumulated probability that at least one of a child's separated parents will enter a new conjugal union, by time since separation and region of Canada, NLSCY, Cycles 1 and 2 (life table estimates)

Why do separated parents in Quebec create new relationships more quickly than they do elsewhere in Canada? Research shows that younger mothers enter new unions more frequently and rapidly than do those who are older when they separate. Are Quebec's mothers younger at separation than they are elsewhere in Canada, or are there other factors at work? Is the discrepancy linked to the fact that cohabitation is so much more common in Quebec than elsewhere, for example? In the next section, we will use event history analysis to attempt to throw some light on these questions.

Entering a new union: a multivariate analysis

Table 1.1 presents the results of two separate analyses exploring the association between certain factors and the frequency and timing of separated mothers' (first column) and fathers' (second column) entry into a new conjugal union. Odds ratios above one show that the variable is positively associated with entering a new union; ratios below one show a negative relationship. For example, the ratio for mother's age in the first column shows a negative relationship; it indicates that the older mothers are when they separate, the less likely they are to enter a new union subsequently.

Table 1.1 Impact of different variables on the likelihood that separated mothers and fathers will enter a new union, Canada, NLSCY, Cycles 1 to 3 (event history analysisa—odds ratios)

Variables Enters a new union
  Mother Father
N 3379 3358
Mother's age at separationb 0.933*** -

Type of union (marriage)
Variables Enters a new union
  Mother Father
Cohabitation 1.037 0.961
Union duration at separationb 1.036** 1.030***

Custody and contact at separation (with mother/regular contact with father)
Variables Enters a new union
  Mother Father
With mother/irregular contact
with father
1.183* 1.381***
With mother/no contact with father 1.558*** 0.790
Shared custody 2.277*** 1.228
With father 1.934** 0.633**

Region (Ontario)
Variables Enters a new union
  Mother Father
Atlantic Provinces 1.161 0.946
Quebec 1.366*** 1.669***
Prairies 1.136 1.251*
British Columbia 0.940 1.104

Previous analyses have demonstrated that children born within marriage are less likely to see their parents separate than are children born to cohabiting parents. Results here suggest that this difference does not persist after parents have separated; once-married mothers and fathers are just as likely to enter new unions as are parents separated from a cohabiting union. In terms of union duration, one might expect that the longer mothers and fathers had been in their relationship before separating, the more cautious they might be about entering a new one. The opposite appears to be the case, however; the longer the union duration, the more quickly mothers and fathers found a new partner.

It is sometimes suggested that having the care of children from an earlier union inhibits the formation of a new union. There is some evidence of this in our findings, though the picture is rather more complicated and it is not possible to establish the direction of any relationship. For example, mothers are significantly more likely to enter a new relationship when the children are in shared custody or in the father's custody. However, we do not know whether this type of custody was arranged because the mother had already formed a new attachment, or whether she was more able to form one because children were not in her care all the time. Among mothers who have custody of their children, however, the less time children spend with their non-resident father, the more likely mothers are to enter a new union. Is it easier for all concerned to integrate a new father figure into the family unit when the biological father is less involved?

Having their children living with them full time certainly appears to inhibit new union formation among separated fathers. Custodial fathers are significantly less likely to enter a new relationship than are other fathers who remain closely involved with their children after separation but who do not have sole physical custody. Most likely of all to enter a new relationship are non-resident fathers who have only limited contact with their children after separation; once again, the direction of the relationship is not clear.

Unfortunately, these findings provide few clues as to why separated mothers and fathers in Quebec create new unions more often and more rapidly than those living elsewhere in Canada. The fact that the significant differences between Quebec and the other Canadian regions persist even after controlling for other variables suggests that neither the higher incidence of cohabitation in Quebec nor the age of mothers at separation is responsible.

New unions and the expansion of children's family life pathways

As we have seen, each conjugal decision taken by a mother or father involves a transition in the life of their children. When parents separate, reconcile or form a different union, the child's family environment is modified accordingly. These are the events that, put together in chronological order, create the family pathways followed during childhood.

In order to reveal something of the diversity and complexity of children's family experience, we reconstructed the family pathways taken by children in the longitudinal sample from their birth to the second survey cycle in 1996-97, when the oldest children in the sample were 13 years old. As it takes a number of years for such life course events to occur, we limited the analysis to children aged 6 years and over at Cycle 2; this left a sample of close to 9000 children aged 6-13 years, with an average age of approximately 10 years in 1996-97. The following analyses portray, therefore, the experience of Canadian children born during the second half of the 1980s (between 1983 and 1991).

Figure 1.5 traces the most common family pathways travelled by children born within a union between birth and 1996-97. Each arrow represents a transition, in terms of parents entering or dissolving a conjugal union; each box represents the presence or absence of new parent figures in the child's family network as a result of the transition. It should be read from the top as follows:

  • The first box represents the starting point for all children born within a couple. At this point in 1996-97, there were still children whose parents had not separated at any time, and who had therefore lived no family transition.
  • The arrows to the next level represent the first family transition, usually when parents separated, occasionally when a parent died. Children who had lived through only one transition by the time of the survey had no new parent figures in their lives.
  • Four types of transition were possible for children whose parents had separated: their parents got back together, their mother or father entered a new union, or a parent died.
  • Children who had seen two transitions between birth and 1996-97 were back with their two parents, had a new mother or father figure in the family environment, or had only one living biological parent.

These pathways continue down, getting even longer when both parents entered a new union, or if a new union ended. Some children had experienced as many as four or five transitions.

Figure 1.6 puts numbers on the pathways shown in Figure 1.5, showing the proportion of children taking these different routes. Each box gives the number of children (per 1000), aged 6-13 years in 1996–97 and born within a couple, who had followed a particular pathway to that point. By Cycle 2, for example, 28 children (per 1000) had parents who had separated and were each living with a new partner in 1996–97; these children had lived through three family transitions by the time of the survey, and their family environment included their two biological parents plus an additional mother and father figure.

This figure shows the following:

  • The majority of children (778, or 77.8 percent) had lived continuously with both biological parents from birth up to the time of the survey.
  • More than one fifth of children (210) born to married or cohabiting parents had experienced their parents' separation by 1996–97.
    • Only a third (68) of these children lived through no other transition before the survey. The rest lived through at least one other transition—in most cases, the arrival of a new mother or father figure. A small proportion had also witnessed the departure of one or more of these extra parent figures.
    • The parents of 24 children were reunited at some point after the initial separation, although 4 had already parted company again by the time of the survey.

Each "level" in the diagram is equivalent to the number of family transitions a child had experienced as of 1996–97. Summing the numbers at each level gives the number of children (per 1000) who had lived through a particular number of family transitions by the survey. For every 1000 children born in a couple, 80 children (68 + 12) had seen only one transition, 78 children had seen two transitions (20+35+20+3) and 64 had seen three or more (4+10+28+7+7+1+7). Altogether, 22 percent of children born within a couple between 1983 and 1991 had experienced at least one family transition as of 1996–97. As we see in the next section, however, family pathways through childhood are closely linked to the conjugal situation of parents when their child is born.

Family life pathways and the context at birth

There is increasing diversity in the context within which Canadian children are born. Marriage, in particular, is losing its monopoly on family life, and growing proportions of children are born either to cohabiting parents or outside a union altogether. Whereas 85 percent of the oldest NLSCY children (1983–84 cohorts) were born to married parents, this was the case for under 70 percent of the youngest ones (1997–98 cohorts at Cycle 3) (When Parents Separate: Further Findings from the National Longitudinal Survey of Children and Youth, 2004-FCY-6E). Whether children are born within marriage, within a cohabiting union or outside a union altogether is closely linked to a child's subsequent family life course. Cohabiting parents are more likely to separate than married parents, for instance, while children born outside a union start life within an entirely different family context. In our sample, 80 percent of the children were born to married parents, 13 percent to cohabiting parents and 7 percent to a lone parent; in the following sections, information about children's family life pathways is presented separately for each group.

Born to a single parent

Children born to a single mother are essentially born to "separated" parents; they experience life in a lone-parent family from birth, which is a very different matter from arriving there as a result of parental separation. For these children, the formation, not the dissolution, of a conjugal union is the first family transition. Figure 1.7, which presents the most common pathways followed by the 7 percent of children in our sample born outside a conjugal union, shows what this means for the family life course.

  • Children born to a lone parent are much more likely to experience family change than those born within a union: only 16.2 percent had experienced no family transitions.
  • The fact that five sixths (84 percent) of these children had experienced at least one transition by 1996–97 is largely a product of the fact that these "separated" parents are more likely to form a union than couples are to separate.
  • Parents who are not living together at the time of their child's birth are as likely to marry or start living with each other as with somebody else. At some point, over 40 percent[7] of children starting out in a lone-parent family actually experienced intact family life within a union formed by their two biological parents.
  • These unions were not particularly durable and, by Cycle 2, only slightly over half (225 of 417) were still intact. For those whose parents separated, other transitions often followed, either when parents reunited (30) or when one parent entered a union with a different partner.
  • Otherwise, the pathways resemble those taken by other children whose parents have separated, with a strong likelihood that the father, mother or both parents will continue their conjugal life course creating, and terminating, unions with other individuals.
How many family transitions?

By comparing children born to a lone parent with those born to married or cohabiting parents in terms of the number of family transitions experienced between birth and 1996–97, Figure 1.8 clearly shows the association between the context at birth and children's family life pathways. We have already commented on the high proportion of children born outside a union who experience at least one family transition. The contrast between children born to cohabiting rather than married parents is also striking. Half the children in the sample born to cohabiting parents had experienced at least one change in their parents' conjugal situation by 1996–97, and one third had seen at least two. This compares with 18 percent and 11 percent of children whose parents were married. In fact, children born to cohabiting parents reached each level approximately three times as frequently as did children born to married parents.

What does this mean in terms of the child population as a whole? Table 1.2 presents the whole sample of children (aged 6–13 years in 1996–97), according to their parents' conjugal status at birth, and whether or not they had experienced a family transition. Overall, over a quarter (26.7 percent) of the children saw at least one family transition between birth and 1996–97. Almost two thirds (65.7 percent) of children in these birth cohorts had a "traditional" childhood, in the sense that they were born to, and lived with, married parents at least up to the time of interview in 1996–97. This is ten times the proportion of children born to and raised by cohabiting parents (6.4 percent).

Table 1.2 Distribution of children aged 6–13 years in 1996–97, according to family transitions experienced since birth and their parents' conjugal status, NLSCYa
Family transitions between birth and 1996–97 Parents' conjugal status at child's birthb Total
Marriage Common-law union Born to a single mother
  % % % %
No transitions 65.7 6.4 1.2 73.3
At least one transition 14.3 6.4 6.0 26.7
Total 80.0 12.8 7.2 100.0

For children born in the 1980s, therefore, having married parents meant less exposure to family change: altogether, the 20 percent of children in these cohorts born outside legal marriage account for close to half the children who experienced some form of family change. Nonetheless, because four out of five children in the 1983–91 cohorts were born within marriage, marital separations (14.3 percent) were more common in the population as a whole than were separations among cohabiting unions (6.4 percent). This may change in coming years as the context within which Canadian children are born evolves. The proportion of extra-marital births rose steeply during the 1990s; by 1997–98, almost one-third of births occurred outside marriage (22 percent to cohabiting couples and 10 percent outside a union), with particularly high rates in Eastern Canada and Quebec, at 39 percent and 55 percent respectively (When Parents Separate: Further Findings from the National Longitudinal Survey of Children and Youth, 2004‑FCY‑6E). If the association between birth context and family life course continues, this evolution means that the proportion of children following the complex family pathways described here will rise.

What type of transitions?

It is possible to calculate the frequency of a particular type of transition from the numbers given in Figures 1.6 or 1.7, by summing the number of children who travelled a particular pathway. For example, in Figure 1.6, the total number of children whose mother formed a new union after separation from the father is equal to 70/1000, and includes the children whose mother entered a new union and remained within it (20); those whose mother separated from the new union (7); those whose two parents formed a new union and remained within it (28), and those whose father (7), mother (7) or two parents (1) separated from their second union.

Table 1.3a Percentage of children (aged 6–13 years in 1996–97) who have experienced different types of family transition, according to the type of union at birth, NLSCYa
Type of family transition Marriage Common-law union Total
% Of separated parents
% Of separated parents
Parents separate
11 48
13 21
Parents' reconciliation 2   6   2
Mother forms a new union
End of mother's new union 1 5 6 12 2
Father forms a new union 7
End of father's new union 1 8 5 11 2

a Longitudinal sample present at Cycles 1 and 2.

The proportions of children making the six most common transitions have been summarized in this way. The proportions are presented in Table 1.3a for children born within a union and in Table 1.3b for those born to a lone parent. Altogether, the parents of over one fifth (21 percent) of children born within a union had separated at some point before 1996–97. Subsequently, of children with separated parents, the following apply:

  • One tenth saw their parents get back together again at some point (though not always permanently).
  • One third acquired a new father figure when their mother entered a union with a different partner.
  • Over 40 percent acquired a new mother figure when their father entered a union with a different partner.
  • Some children had already experienced another separation by 1996–97. One child in ten had seen their mother's new relationship end; the same proportion had seen the end of their father's new union.

Parental separation was much more common among children of cohabiting (48 percent) than married (17 percent) parents. The proportion experiencing their mother's new union (17 percent versus 6 percent) or their father's new union (20 percent versus 7 percent) was also higher. However, what really distinguishes cohabiting parents from married parents is their propensity to separate. The fact that almost three times the percentage of children born to cohabiting parents acquired additional parent figures through their mother's or father's new union is a direct consequence of the higher proportion whose parents separated in the first place. After separation, as the figures in italics in Table 1.3a show, formerly married mothers and fathers are just as likely to enter new unions as are formerly cohabiting parents. In both cases, approximately one third of separated mothers and just over 40 percent of separated fathers entered a new union. Once formed, however, these subsequent unions are also less durable among parents who were living together than they were if the parents were married at their child's birth.

Table 1.3b Percentage of children aged 6–13 years in 1996–97, born to a single mother, who had experienced different types of family transition by 1996–97, NLSCYa
Type of family transition Born to a single mother %
Parents marry or start living together 42
Parents separate 19
Mother forms a union with another partner 31
End of mother's union 7
Father forms a union with another partner 35
End of father's union 6

a Longitudinal sample present at Cycles 1 and 2.

Among children born outside a union, the pattern was rather different. As Table 1.3b indicates, being born to a lone mother does not necessarily mean growing up in a single-parent family.

  • Over 40 percent of these children spent some time in an intact family when their biological parents moved in together; almost half of those whose parents reunited (19 percent) however, had also experienced the end of this episode.
  • The mothers of close to one third (31 percent) of these children had entered a union with someone other than the child's father; almost a quarter of these unions had already ended (7 percent).
  • An even higher proportion of fathers (35 percent) had entered a union with someone other than the child's mother; five sixths of these unions were still intact at the survey.
Same family type, different family pathway

Finally, the pathway diagrams illustrate another important feature of the family life course: that several different pathways may lead to a given family situation at a particular time. The four shaded boxes in Figures 1.6 and 1.7 each represent a group of children who were living with both biological parents in 1996–97. The pathway leading to each one reveals a different route into an intact family: a) together from birth; b) together at birth, separated and reunited; c) united after the child's birth; d) united after the child's birth, separated and reunited. Children who at one time live in an intact family may have also experienced life with a single parent.

It is important in family research to understand these distinctions, and to take account of the pathway leading up to any given "family structure." Research into the impact of family change on child outcomes, for example, has tended to treat lone-mother families as a homogeneous group. The experience of children living with a lone mother from birth, however, has very little in common with that of children who find themselves with a lone mother following parental separation. Similarly, the experience of stepfamily life will vary considerably according to the pathway leading to it; children born outside a union and living with a stepfather from infancy will have a very different experience from that of children acquiring a stepfather later in life, after a period in an intact family.

Although these life course diagrams illustrate the diverse and complex nature of children's family life experience today, they nonetheless simplify the real situation, as they include only transitions resulting from conjugal life decisions made by parents; the diversity is all the greater when changes in the sibling network are taken into account.


When separated parents form new relationships, they may introduce more than an extra parent figure into their children's family universe. New partners may themselves be separated, with children of their own from an earlier union; these "stepsiblings" expand the child's family environment still further. Later on, half-siblings may be added to the already extended family network, as newly formed couples decide to have children together. In this section, we focus on the expansion of the sibling network, using data from all children in the Cycle 2 sample whose mother or father entered a union with someone other than their child's other biological or adoptive parent.[8]

Living with stepparents, living with stepsiblings

Co-residence patterns are an interesting feature of step-relationships, and are the direct result of the tendency of children to continue living with their mother when parents separate. First, children are much more likely to live with their mother's new partner than with their father's new partner. In this sample, for example, whereas 84 percent of children lived full time with their stepfather, only 6 percent did so with their stepmother; in fact, under 15 percent of children lived with their father's new partner even part of the time. Second, stepsiblings rarely share the same residence. Only if both partners in the new couple have full custody of children from earlier unions are stepsiblings part of the same family unit on a full-time basis. They share a residence part of the time when both partners have at least shared custody. In general, children have contact with their stepfather's children only when the latter come to visit him; they have contact with their stepmother's children, on the other hand, only on visits to their father.

Figure 1.9 Proportion of children aged 0–13 years in 1996–97 whose mother or father formed a new union, according to the existence of stepsiblings, and whether they share a residence with them on a part- or full-time basis, NLSCY, Cycles 1 and 2

Figure 1.9 gives the distribution of children whose mother or father formed a new union, according to whether the new parent figure had children from an earlier union, and whether children shared a residence with these stepsiblings. Overall, close to half the new relationships formed by separated parents were with individuals who already had children from an earlier union: only 59 percent of mothers' new unions and 51 percent of fathers' new unions did not bring extra siblings into the family network. Only 8 percent of children whose mother formed a new union lived full time with their stepfather and his children, and only 2 percent of those whose father had a new partner lived with their stepmother and her children. Although children do not often share a residence with their stepsiblings, they appear to do so more frequently, nonetheless, with their stepfather's children than with their stepmother's children. Approximately two fifths of children whose stepfather had children from an earlier union lived with these stepsiblings, at least part time; this was the case for a much lower proportion of those with stepsiblings from their father's new union.


Another event, occurring later on, may also have an impact on a child's relationship with his parents—the arrival in his life of a half-sibling, when one parent has a child with a new partner. This is a relatively common occurrence: by 1996–97, 28 percent of mothers' new unions and 24 percent of fathers' new unions were fertile. Evidently, since it follows a parent's entry into a new union, the likelihood of acquiring a half-sibling increases with the time since separation. Figure 1.10 presents the proportion of new unions (mothers' and fathers') within which a child is born, according to the time elapsed since separation. This figure includes only children whose parents separated at some point during their childhood; children born to a lone mother who never lived with their biological father are excluded.

Figure 1.10 Among children whose separated mother or father formed a new union, the proportion whose parent had a child with a new partner, according to the time elapsed since separation, NLSCY, Cycles 1 and 2

Although fathers enter new unions more rapidly than do mothers, mothers tend to have babies earlier on: two to three years after separation, 15 percent of mothers who had formed a new relationship had had a child, compared with only 8 percent of fathers. Men gradually caught up, and nine years or more after the separation, approximately 40 percent of fathers and mothers who had entered a new union had started a second family.

The earlier arrival of babies within mothers' new unions cannot be explained entirely by the fact that women's fertility cycle tends to end earlier than that of men. Research has shown that one of the key factors in stepfather family fertility is the age of the mother's youngest child at the start of the new union (Juby, Marcil-Gratton and Le Bourdais, 2001). It is possible that mothers, whose children generally live with them after separation, prefer to have an additional child rapidly, in order to minimize the age difference between siblings. For fathers this is generally less of a preoccupation, as their children from different unions are less likely to be part of the same family day to day.

How positively or negatively children experience the arrival of a half-sibling will largely depend on how it affects the contact they have with their parents. Once again, we would expect these adjustments to be more of a challenge when the father has an additional child; any time and money invested in his new baby will usually be invested in a different household from the one in which his other children live.

Half-siblings and stepsiblings

For some children, a new parent figure signifies the expansion of the family environment to include both stepsiblings and half-siblings. Figure 1.11 shows how the sibling network developed for children who acquired a new father or mother figure. Over 60 percent of children whose mother entered a new union, and close to two thirds of those whose father did so, saw their sibling network expand with the arrival of stepsiblings, half-siblings or, for 1 child in 10, both types of sibling. Although stepsiblings make up the majority of new siblings, as children progress further along their life course, and as parents have more time to establish new families, the proportion of children with younger half-siblings may eventually exceed that of stepsiblings.

Figure 1.11 Proportion of children aged 0–13 years in 1996–97, whose mother or father created a new union, according to the presence of stepsiblings or half-siblings in their family network, NLSCY, Cycles 1 and 2

The extended sibling network

From the point of view of the child whose separated father or mother has children within a new union, these half siblings are, by definition, younger. From the point of view of the child born within these new unions, on the other hand, half-siblings are, by definition, older. In other words, children acquire half-siblings in one of two ways: a) they gain younger half-siblings when a biological mother or father has a child within a new relationship; b) they gain older half-siblings by being born into a "stepfamily" environment—one in which the mother or father already have children from an earlier union. So far, we have only considered the arrival of younger half-siblings in a child's family network. Nonetheless, as mentioned in an earlier report (When Parents Separate: Further Findings from the National Longitudinal Survey of Children and Youth, 2004-FCY-6E), 13 percent of children in the NLSCY longitudinal cohort were born into the second family of one or both parents; this meant they had half-siblings in their family from birth.

In the child population as a whole, aged 0–13 years in 1996–97, close to one tenth of children had maternal half-siblings, and almost the same proportion had paternal half-siblings. In both cases, approximately one third of half-siblings were younger, and two thirds older, once again because of the young age of the sample. As their life course progresses, many other children will acquire younger half-siblings, as biological parents separate and start new families. Having both older and younger half-siblings is very rare. This occurs either when one parent has children in three separate families, or when one parent has children from an earlier union, and the other has children in a subsequent one.

In terms of the extended sibling network, therefore, children may have older or younger half-siblings or stepsiblings. Unlike half-siblings, who remain "part of the family" irrespective of conjugal decisions made by parents, stepsiblings may be only temporary figures in a child's extended sibling network; when a mother or father separates from their new partner, the children of this new partner are likely to leave the family environment with their parent. Figure 1.12 shows the distribution of the whole sample of children, aged 0–13 years in 1996–97, according to their half-sibling and stepsibling network; information on stepsiblings refers to the proportion of children who had experienced the arrival of stepsiblings at some point, and does not necessarily imply that they were actually present in the family environment in 1996–97.

  • Altogether, almost one in five children had at least one stepsibling or half-sibling.
  • Children born into a stepfamily environment (with older half-siblings) represent the largest proportion of children with an extended sibling network.
  • Only 3 percent of children had both stepsiblings and half-siblings.

Figure 1.12 Distribution of children aged 0–13  years in 1996–97, according to whether stepsiblings or half-siblings have been part of their family network, NLSCY


Separation is often just the first of a series of changes affecting children, whose relationship with their biological parents continues even after the latter have gone their separate ways. It is just the beginning of a process that generally leads to a rapid expansion of the child's family environment to include new "parents", stepsiblings and half-siblings. The life course diagrams highlight just how diverse the family experience and environment have become for the ever-increasing group of children with biological parents living separately.

Although most of the children in the sample used for these analyses had not yet reached age 10, over a quarter of them had already lived through at least one transition, and one in five had a sibling who was not a full sibling. As children progress further along their life course, and as more parents separate and enter new unions, these complex life courses will become more frequent and increasingly diverse.

One reason why life courses are so complex is that, once parents separate, their children's family potentially expands in two directions. Although some non-resident parents lose contact with their children, the majority continue to play a central role in their lives.

It is important, therefore, not to limit the analysis of family change, and its impact on children, to the residential group. Children are likely to be as affected by the arrival of new "family" members in the life of either the non-custodial or custodial parent. Although they rarely live with their stepmother's children, these non-resident stepsiblings do have an impact on their lives. They may, in fact, be as affected by children who live with their non-resident father as by stepsiblings with whom they reside—both in emotional terms, and in terms of the time and money their non-resident father has to invest in them.

Perhaps the most important policy contribution of these analyses is to promote awareness of the fluidity and diversity of family life. It is essential to appreciate the shifting nature of family circumstances after separation in order to avoid simplistic solutions to complex situations. In many cases, for example, arrangements made at separation in terms of custody, visiting and child support will need to be modified in response to changes in mothers' or fathers' conjugal or parental situation. Questions related to the competing demands of different children in a parent's life are also becoming more urgent, as increasing numbers of parents are responsible for children from two or more unions.

Finally, with growing numbers of adults and children in step-relationships, the issue of stepparents' rights and responsibilities is likely to become more rather than less important, especially since most stepfathers are not legally married to the mother of their stepchildren. Evidently, the rights and responsibilities of stepparents are in some ways related to the role they play in the lives of their stepchildren. Although a large body of research on stepfamilies exists, few studies have examined how children integrate these new "actors" into their family universe. This question is the focus of the next section of this report.

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