Research shows negative effects of half-siblings

August 11, 2013, American Sociological Association

Adolescents who have half-siblings with a different father are more likely to have used drugs and had sex by age 15 than those who have only full siblings. That's according to new research from Karen Benjamin Guzzo, an assistant professor of sociology at Bowling Green State University, and Cassandra Dorius, an assistant professor of human development and family studies at Iowa State University.

Using data from the National Longitudinal Study of Youth, they examined a phenomenon known as "multi-partnered fertility" or MPF. This happens when parents who are not romantically involved with each other form new relationships and have another child with a new partner.

"It's not new behavior, but it's happening more often as more people are having children outside of marriage," said Guzzo.

According to Guzzo, this is one of the first studies to examine the effect of parental MPF on children over the long-term, and the only study that takes into account background factors (such as the mother's level of education and household poverty) and the number of changes in family structure the adolescent experienced.

The researchers looked at the connections between this re-partnering and additional on adolescent and early sex. They focused on mothers and first-born children who lived with their mother most of their lives.

"For children, MPF means having a half-sibling, but it also means, for first-born children, that they usually experienced their splitting up—if they were together at all, lived in a household for some time, experienced their mother finding a new partner at least once and perhaps lived with a stepfather, and finally experienced their mother having a baby with a ," Guzzo explained.

Researchers looked at the mother's , her own family structure growing up, and whether the child experienced bouts of poverty. They also examined —whether the father lived with them at birth, how many family transitions the adolescents experienced, and whether the mother ever married or cohabited, with the child's father or another partner.

"We find that first-born adolescents with half-siblings with the same mother but a different father do have less favorable outcomes compared to their peers with only full siblings, even after accounting for the mother's background characteristics, socioeconomic factors the child experienced growing up, and family instability and structure," Guzzo said.

"Adolescents with a half- with a different father are about 65 percent more likely to have used marijuana, uppers, inhalants, cocaine, crack, hallucinogens, sedatives, or other drugs by the time of their 15th birthday than those who have only full siblings. They are also about 2.5 times more likely to have had sex by their 15th birthday than their peers with only full siblings."

Guzzo said it's not clear yet what drives these outcomes, but that in the future she and Dorius plan to explore differences in maternal behaviors, father and stepfather involvement, and adolescent perceptions of their relationship with their mother to see if these factors explain the association between having half-siblings with a different father and risky adolescent behavior.

"We are also planning to look at whether this association holds for children other than the first-born, who tend to experience the most instability," Guzzo said.

Explore further: When Mom Dates, Dad Stops Visiting His Kids

More information: The paper, "Maternal Multipartnered Fertility and Adolescent Well-being," will be presented on Tuesday, Aug. 13, at 12:30 p.m. EDT in New York City at the American Sociological Association's 108th Annual Meeting.

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2.6 / 5 (5) Aug 11, 2013
Um. So, any studies on children in broken homes who don't have half-siblings? That not enter into the equation at all? Was this a spurious one-off supposition that somehow the actual half-sibling is somehow responsible or emblematic of whatever is supposed to have occurred? Any concern that it was somehow the parents who might have changed their attitudes towards what essentially is a reminder of a former relationship, and maybe neglected or abused the child from the former relationship? Any word on the parent who was involved in making the first child and their involvement in their child's life?

Honestly, this brings up more questions than it answers, one of which is: "what the heck were they trying to prove?"
5 / 5 (1) Aug 11, 2013
Were polygamous marriages involved in the study? Does this hold true for them? What happens with paternal siblings?
not rated yet Aug 12, 2013
I wouldn't have minded having the results of this study compared with an opposite scenario:half-siblings who share a father, but not a mother. Also, this study seems to imply that they only looked at children who were living with their mother; there was no mention if 1st-born children living with their father (with perhaps the younger half-sibling living with the 'shared' mother) would conform to the data too. They seem to focus on the income of the mother, but not the contributions of the father, which can be a factor too. A father refusing to pay child-support will also generate more resentment (-ve contributory impact) in the child.That might have put some perspective back in. I can't help feeling that the limited parameters of this study are are hinting indirectly at the old classical parental 'blame game' (blame the mother when things are less than ideal, in this case) Regards, DH66
2.6 / 5 (5) Aug 12, 2013
Because it is most often the mother who retains custody of the child after a divorce, it is HER behavior that is called into question and it is her sense of responsibility and degree of emotions such as love and caring that, failing a clear presence of such feelings toward any of her children, may be the catalyst that produces negative feelings (possibly jealousy) toward a younger half-sibling. Children, whether the oldest, youngest or middle, can sense when the mother is stressed and also when she is unhappy such as in a failing relationship, and usually the oldest child tries to alleviate the mother's unhappiness by taking on some responsibility, at least temporarily. But sometimes the older child may become resentful if the mother doesn't help herself and she may blame the older child for not doing a better job as a baby sitter or some other reason.
There is no clear answer to such a situation, but the appearance of the child's father usually gives him some sense of proportion.
2.6 / 5 (5) Aug 12, 2013
IMO, this study only helps to promote further the need for a normal family unit of a mother and father who prove to be responsible parents even if poor. At a very young age, children aren't even aware that they're poor, and even when they are older and the loving family unit is intact and both the mother and father have excellent parenting skills, the children are able to weather most adverse conditions. The feelings of security and being wanted and loved are paramount to a healthy upbringing for any child. In a broken home, if the older child is able to see his father, even occasionally, it gives him a sense of knowing where he came from, and can take a little pride and satisfaction in that.
2 / 5 (4) Aug 14, 2013
The evidence is overwhelming. Traditional families: 1 Man + 1 Woman in 1 Marriage, where children are born after Marriage is the best for raising well adjusted children.

Who has always believed this.... Conservatives.....Christians......
Who doesn't believe this..... Progressives.....
Who works to destroy Traditional families...... Progressives...Homosexual activists...

1 / 5 (3) Aug 16, 2013
From time immemorial, the family unit of a loving father and mother protecting, nourishing and encouraging their children has been the basis for a healthy society. Good morality is most often learned from the natural parents and, even when one parent dies, the surviving parent can continue the raising of their children in a healthy atmosphere as though both parents were present.

A young mother or father who have lost their spouse is very likely to seek out another for companionship, support, love and physical pleasure, and as a surrogate parent to their own child. But a continuation of a normal and happy childhood is largely dependent on the mother, or even a stepmother to bring the family closer together where everyone is treated equally and fairly. Jealousy occurs if an older child perceives favoritism toward a younger or middle sibling or half-sibling. Therefore, it is most important for the female parent to be well informed as to her responsibilities and what's expected of her.
1 / 5 (2) Aug 16, 2013
The evidence is overwhelming. Traditional families: 1 Man + 1 Woman in 1 Marriage, where children are born after Marriage is the best for raising well adjusted children.

Who has always believed this.... Conservatives.....Christians......
Who doesn't believe this..... Progressives.....
Who works to destroy Traditional families...... Progressives...Homosexual activists...
Many cultures have extended families. The Danes do better than you on almost every metric and their children are reared by multiple parents
1 / 5 (3) Aug 16, 2013
Assuming that you mean grandparents, uncles, aunts, brothers and sisters - yes, that is how it was in America once upon a time. While it is still that way in many families, the actual parents always have the last word with regard to legal considerations for their children.

However, if you mean that children in Denmark are shunted off to live with or be supervised by other than their natural parents, grands, uncles and aunts, etc., that is a double-edged sword. That mostly describes, IMO, Hillary Clinton's "It takes a village..." where all the adults in a society or tribe have certain rights regarding a child's welfare. That is fine if all other people only have the child's best interests in mind, but WHAT are the interests of those adults regarding the child. Strangers, even married couples in a village are better off to return a lost child to its parents or very close relative rather than taking on the burden of caring for the child. No one knows the child better than its own parents
1 / 5 (3) Aug 16, 2013
Israel also had such a program where babies were taken away from their parents to be raised by paid caregivers, and the parents were allowed to see their own child on weekends, because the rest of the week, they had to work long hours in the fields, factories, etc. The Kibbutz were a successful program as far as the growth of the overall society in each region of Israel where they were able to flourish. They were successful only due to the dedication of the workers taking part in the program. If any part of the group did not do their part working hard for the good of all, they were asked to leave. Otherwise, the program would fail when all the parts are dependent on each other like a well-oiled machine. This was true Communism. In the Kibbutz, EVERYONE worked without exception and even the desk jockeys had to take a turn in the field and factories.
But the babies were not with their loving parents and the caregivers could not provide the love as their time with each child was limited.
not rated yet Aug 24, 2013
"Guzzo said it's not clear yet what drives these outcomes..."
MLP factors are not stated to be drivers.
Readers here prove me wrong... when I assert you can not read more into this study than what the authors presented.

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