How life outcomes for children with same-sex parents might differ from those raised in traditional unions has been the subject of a large body of academic research. In advance of the Supreme Court’s June 2015 ruling on same-sex marriage, the American Sociological Association prepared an amicus brief that reviewed prior studies on the subject.

In the brief the ASA researchers wrote:

We conclude that there is a clear consensus in the social science literature indicating that American children living within same-sex parent households fare just as well as those children residing within different-sex parent households over a wide array of well-being measures: academic performance, cognitive development, social development, psychological health, early sexual activity, and substance abuse. Our assessment of the literature is based on credible and methodologically sound studies that compare well-being outcomes of children residing within same-sex and different-sex parent families. Differences that exist in child well-being are largely due to socioeconomic circumstances and family stability.

A 2012 study by Mark Regnerus of the University of Texas at Austin, included in the ASA’s literature review, was based on a large, nationally representative random sample of young adults from the New Family Structures Study. A total of 15,058 individuals between 18 and 39 were contacted and screened, and 2,988 were given full surveys. Based on analysis of the survey information, the study concluded that the NFSS “clearly reveals that children appear most apt to succeed well as adults — on multiple counts and across a variety of domains — when they spend their entire childhood with their married mother and father, and especially when the parents remain married to the present day.” When it was released, the U.T. Austin study received significant support and criticism, even as its methods and conclusions were drawn into question by a large number of sociological researchers.

In a 2015 study published in the July 2015 issue of Social Science Research “Measurement, Methods and Divergent Patterns: Reassessing the Effects of Same-sex Parents,” Simon Cheng of the University of Connecticut and Brian Powell of Indiana University, Bloomington, re-analyzed the publicly available data from the 2012 study. The scholars examined the extent to which the differences found in the original research were attributable to the ways in which family types were defined, and to other analytical and methodological choices.

A particular challenge involved defining and classifying family types: In the original 2012 paper, respondents were considered to be from “intact biological families” if they reported having lived with both their biological mother and biological father from birth until age 19. However, a substantial proportion of these respondents had been removed from this category because their parents were not married at the time of the interview. This potentially over-inflated the positive impact of growing up in an intact biological family, as those whose families may have been unhappy or dysfunctional were not considered to be part of this group. The authors also found that certain methodological decisions increased the number of differences between the outcomes of adult children of same-sex parents compared to adult children of intact biological families.

Nearly 35% of the respondents classified as having been raised in same-sex families provided answers for other questions on the survey that called their data into question. Approximately one-third of the respondents who the original analyses considered to have been raised in same-sex families never lived with the lesbian or gay parent, and half never lived with the lesbian or gay parent’s partner. Of the 236 respondents classified as having been raised in a same-sex household, only 51 could be reasonably understood to have lived in a two-parent same-sex household for at least a year.

After correcting a number of methodological issues — misclassification of data or variables, and use of inappropriate statistical tests — the authors re-ran the original analyses multiple times using different corrective methods.

The paper’s findings include:

• After correcting for errors, adding appropriate control variables, recoding race/ethnicity to reflect multiple (instead of two) categories, and controlling for the effects of misclassified or uncertain data, the authors found only six differences between adult children of lesbian mothers and intact biological families, and three differences between adult children of gay fathers and intact biological families.
• Of the differences found among adult children raised by lesbian mothers, three were extremely questionable, and disappeared following the deletion of one or two extreme data points that were driving the differences. Of the remaining three differences, two were not considered to be objectively worse for either group (identifying as homosexual, and having had a same-sex relationship), leaving only one statistically significant difference between adult children raised by lesbian mothers compared to adult children raised in intact biological families.
• Among the 51 respondents who were identified as having lived in a two-parent same-sex household for at least a year, only four significant differences were demonstrated. Of these, two were not objectively worse (identifying as homosexual and having had a same-sex relationship), and two did not take place during adulthood (receiving public assistance in childhood, and sense of safety and security growing up), and therefore cannot be reasonably considered consequences of their childhood family situation.

“The reanalysis [of the source data] offers evidence that the empirical patterns showcased in the original Regnerus article are fragile — so fragile that they appear largely a function of these possible misclassifications and other methodological choices,” the authors state. “Our replication and reanalysis of Regnerus’s study offer a cautionary illustration of the importance of double checking and critically assessing the implications of measurement and other methodological decisions in our and others’ research.”

Further reading: A 2015 research roundup, “Same-sex Marriage and Big Research Questions Behind the Debate,” gathers together research questions and provides links to associated resources that can help analysts and reporters go beyond the headlines.

Keywords: parenting, LGBT, lesbian mothers, gay fathers, same-sex parents, same-sex parenting, children, family structure, sexuality