Optimally, you’ve got the input from both [a mother and a father] and the children brought up in those circumstances are, as a cohort, better off than those who are not. … whether it’s in terms of health outcomes, mental health, physical health, whether it’s in terms of employment prospects, in terms of how this is generated from one generation to another, the social science evidence is overwhelmingly in one direction in this regard. – Liberal MP Kevin Andrews, excerpts from an interview on Sky News, August 13, 2017.

Public campaigns for and against same-sex marriage have been heightened by the Turnbull government’s plan to conduct a $122 million voluntary postal survey asking the nation whether same-sex couples should be able to marry under Australian law.

Discussing his opposition to same-sex marriage during an interview on Sky News, Liberal MP Kevin Andrews said children who are brought up with a mother and a father “are, as a cohort, better off than those who are not”.

Andrews also said the “social science evidence is overwhelmingly in one direction in this regard”.

Let’s look at the research.

Checking the source

When asked for sources to support his statements, a spokesperson for Kevin Andrews told The Conversation:

Mr Andrews wrote a book called “Maybe I Do”. You might also like to look at the 2011 report, For Kids’ Sake, by Professor Patrick Parkinson of the University of Sydney and studies by Douglas Allen (2015) in Canada and Paul Sullins (2015) in the US.

Verdict

Kevin Andrews’ assertion that children who are brought up with a mother and father are, “as a cohort, better off than those who are not” is not supported by research evidence.

The majority of research on this topic shows that children or adolescents raised by same-sex parents fare equally as well as those raised by opposite-sex parents on a wide range of social, emotional, health and academic outcomes.

Response to Kevin Andrews’ sources

First of all, let’s look at the sources provided by Andrews’ spokesperson to support his statements. A summary of Kevin Andrews’ book on the National Library of Australia website says it:

… reviews the evidence on the benefits of marriage for society, children, and adults. It argues that healthy, stable, and happy marriages are the optimal institution for promoting individual well being and healthy societies.

It’s true that there is a large body of evidence to show that stability in marriage and family life is beneficial for children, particularly in early childhood. Some research has shown that these benefits are associated with higher average income and education levels among married couples, rather than marriage itself.

But these studies didn’t involve comparisons between opposite-sex and same-sex married couples, so they do not defend the argument that heterosexual marriage leads to better outcomes for children than same-sex marriage. In fact, some research suggests same-sex marriage would provide benefits for children being raised in these families.

Patrick Parkinson’s report, For Kid’s Sake, links rising rates of divorce, family conflict and instability in parental relationships with increasing psychological distress among young people in Australia. One of Parkinson’s conclusions was that:

the most stable, safe and nurturing environment for children is when their parents are, and remain, married to one another.

There are studies that support these assertions. This research supports the importance of family stability, quality relationships between parents and children, and the need for access to socioeconomic resources – but not the need for parents to be heterosexual.

Douglas Allen’s 2015 paper is a critical, but not systematic, review of more than 60 studies relating to same-sex parenting and/or child outcomes. This paper does not present findings related to child outcomes.

Rather, Allen says that, due to sampling bias and small sample sizes in the existing body of work, there is currently no conclusive scientific evidence demonstrating that children raised by same-sex couples do better or worse than children raised by heterosexual couples.

Andrews’ spokesperson also pointed to 2015 research from Paul Sullins. Sullins’ 2015 analysis of data from the US National Health Interview Survey indicated that children raised by same-sex parents were more than twice as likely to experience emotional problems than those raised by heterosexual, married parents who were biologically related to their children. But this analysis was criticised for not taking into account the stability of the family environment.

The author combined all children in same-sex families into one category, while placing children in opposite-sex families into separate categories – including different categories for step-parents and single parents, for example. So the comparison made was between all same-sex parented families, and a selection of stable heterosexual families.

Research on outcomes for children in same-sex parented families

Now let’s look at other studies that have been conducted around the world. Many of these studies examine the outcomes for children in same-sex parented families where both parents are women. There has been comparatively little research on families in which both parents are men. It can be difficult to achieve adequate sample sizes of children raised in two-father families, given the small number of these families. There is no research showing that children raised by gay fathers fare worse than other children.

A study published in 2016 using data from the US National Survey of Children’s Health for 2011-12 compared outcomes for children aged six to 17 years in 95 female same-sex parented families and 95 opposite-sex parented families.

The study found no differences in outcomes for children raised by lesbian parents compared to heterosexual parents on a range of outcomes including general health, emotional difficulties, coping behaviour and learning behaviour.

A paper published for the American Sociological Association in 2014 reviewed 10 years’ of scientific literature on child well-being in same-sex parented families in the US. The literature review covered 40 original published studies, including numerous credible and methodologically sound social science studies, many of which drew on nationally representative data.

The authors concluded there was clear consensus in scientific literature that children raised by same-sex couples fared as well as children raised by opposite-sex couples. This applied for a range of well-being measures, including:

academic performance

cognitive development

social development

psychological health

early sexual activity, and

substance abuse.

The authors noted that differences in child well-being were largely due to socioeconomic circumstances and family stability.

A meta-analysis published in the Journal of Marriage and Family in 2010 combined the results of 33 studies to assess how the gender of parents affected children. The authors found the strengths typically associated with married mother-father families appeared to the same degree in families with two mothers and potentially in those with two fathers.

The meta-analysis found no evidence that children raised by same-sex couples fared worse than children raised by opposite-sex couples on a range of outcomes including:

security of attachment to parents

behavioural problems

self perceptions of cognitive and physical competence, and

interest, effort and success in school.

This review included studies from Europe, the UK and the US. The authors said that scholars had achieved

a rare degree of consensus that unmarried lesbian parents are raising children who develop at least as well as their counterparts with married heterosexual parents.

In Australia, a large study published in the peer-reviewed BMC Public Health Journal in 2014 (and of which I was one of five co-authors) surveyed 315 parents representing 500 children. 80% of children had a female same-sex attracted parent, while 18% had a male same-sex attracted parent.

The results did support previous research showing that stigma related to a parent’s sexual orientation is negatively associated with mental health and well-being.

But, overall, the study found children and adolescents raised by same-sex parents in Australia fared as well as children of opposite-sex parents, and better on measures of general behaviour, general health and family cohesion.

A follow up paper published in 2016 found there was no difference between children raised in female same-sex parent households and children raised in male same-sex parent households.

Further work from the same project reported on surveys and interviews with adolescents raised by same-sex parents. This study (of which I was one of four co-authors) did find that some adolescents with same-sex parents reported experiencing anxiety relating to fear of discrimination, which was linked to poorer well-being.

A US study published in 2011 found adolescents raised by lesbian mothers were more likely to have reported occasional substance use, but not more likely to have reported heavy use, than other adolescents.

A 2010 analysis of data from the 2000 US census found that children raised by same-sex couples had no fundamental deficits in making normal progress through school compared to children raised by opposite-sex couples.

When parents’ socio-economic status and the characteristics of the students were accounted for, the educational outcomes for children of same-sex couples couldn’t be distinguished with statistical certainty from children of heterosexual married couples.

Analysing studies that show different results

Some studies have indicated that adults raised by same-sex parents fare worse on some educational, social or emotional outcomes. But the majority of research does not support this. There are also studies that have been published and later discredited, but continue to be used as references.

The 2012 US New Family Structures Study, also known as the “Regnerus study”, is often cited by groups opposed to same-sex marriage.

The study looked at outcomes for adults aged 18-39. It compared outcomes for adults with a parent who had had a same-sex relationship, with outcomes for adults raised by still-married, heterosexual couples who were biologically related to their children. It showed the adults with a gay or lesbian parent or parents fared worse on a range of social, educational and health outcomes. But this study has been very widely criticised.

In a brief filed in the US Supreme Court in 2015, the American Sociological Association said:

The Regnerus study … did not specifically examine children raised by same-sex parents, and provides no support for the conclusions that same-sex parents are inferior parents or that the children of same-sex parents experience worse outcomes.

As outlined by the American Sociological Association, the study removed all divorced, single, and step-parent families from the heterosexual group, leaving only stable, married, heterosexual families as the comparison. In addition, Regnerus categorised children as having been raised by a parent in a same-sex relationship

regardless of whether they were in fact raised by the parent … and regardless of the amount of time that they spent under the parent’s care.

A subsequent reanalysis of the data, using different criteria for categorising respondents, found the results inconclusive, or suggestive that “adult children raised by same-sex two-parent families show a comparable adult profile to their peers raised by two-biological-parent families”.

Strengths and weaknesses of evidence on outcomes for children

The “gold standard” for research on child and family outcomes are studies that involve randomly selected, population-based samples. This has been difficult to achieve in research on same-sex parenting because many population-based studies don’t ask about parents’ sexual orientation. Even where they do ask, not all studies include a sample of children or adults raised by same-sex parents that is large enough to provide for reliable statistical analysis.

This has led to criticism of the quality of evidence on outcomes for children raised by same-sex parents, because most studies have relied on convenience or volunteer samples, which are not randomly selected, and so may include bias.

However, there are methodological limitations in all studies. And, as outlined earlier, recent analyses of population-based data sets have supported the finding that children or adolescents raised by same-sex couples do not experience poorer outcomes than other children. So there is no clear basis to the argument that convenience samples lead to “incorrect” findings due to bias. – Jennifer Power

Review

This FactCheck gives a good broad overview of the research and scientific consensus in regard to child health and well-being in same-sex parent families. The studies included, on balance, represent the current understanding of academics and child health experts on child health and well-being outcomes in same-sex parent families.

The National Lesbian Longitudinal Family Study provides additional evidence to support the verdict of this FactCheck. As a well established and methodologically robust longitudinal study, the National Lesbian Longitudinal Family Study provides important additional insights.

In the Australian context, the 2013 Australian Institute of Family Studies review of same-sex parent families also supports the overall verdict of this FactCheck.

It should be noted that research has indicated that same-sex parent families experience stigma and discrimination, and when they do it can impact on child health and well-being.

Overall, however, the verdict in this FactCheck is appropriate based on current research. – Simon Crouch

The Conversation’s FactCheck unit is the first fact-checking team in Australia and one of the first worldwide to be accredited by the International Fact-Checking Network, an alliance of fact-checkers hosted at the Poynter Institute in the US. Read more here.

Have you seen a “fact” worth checking? The Conversation’s FactCheck asks academic experts to test claims and see how true they are. We then ask a second academic to review an anonymous copy of the article. You can request a check at checkit@theconversation.edu.au. Please include the statement you would like us to check, the date it was made, and a link if possible.