Despite considerable research showing that children of same-sex parents fare just as well as children with heterosexual parents, two papers -- a review of existing studies and a new study -- published June 10 in Elsevier's Social Science Research, find insufficient data to draw any definitive conclusions.

The review by Dr. Loren Marks from Louisiana State University finds that much of the science that forms the basis for the highly regarded 2005 official brief on same-sex parenting by the American Psychological Association (APA) does not stand up to scrutiny. The new study by University of Texas sociologist and professor Mark Regnerus, provides compelling new evidence that numerous differences in social and emotional well-being do exist between young adults raised by women who have had a lesbian relationship and those who have grown up in a nuclear family. Dr. Marks reviewed studies published between 1980 and 2005 cited by the 2005 official APA brief which asserted that: "Not a single study has found children of lesbian or gay parents to be disadvantaged in any significant respect relative to children of heterosexual parents."

"The jury is still out on whether being raised by same-sex parents disadvantages children," explains Marks. "However, the available data on which the APA draws its conclusions, derived primarily from small convenience samples, are insufficient to support a strong generalized claim either way."

Of the 59 studies referenced in the APA brief, more than three-quarters were based on small, non-representative, non-random samples that did not include any minority individuals or families; nearly half lacked a heterosexual comparison group; and few examined outcomes that extend beyond childhood such as intergenerational poverty, educational attainment, and criminality, which are a key focus of studies on children of divorce, remarriage, and cohabitation. In other words, "A lack of high quality data leaves the most significant questions unaddressed and unanswered," concludes Marks.

In his study, Professor Mark Regnerus used data from the New Family Structures Study (NFSS) , a large nationally representative sample of just under 3,000 young Americans aged 18 to 39, to compare how children raised in eight different family structures fared on 40 social, emotional, and relationship outcomes.

According to his findings, children of mothers who have had same-sex relationships were significantly different as young adults on 25 of the 40 (63%) outcome measures, compared with those who spent their entire childhood with both their married, biological parents. For example, they reported significantly lower levels of income, more receipt of public welfare, lower levels of employment, poorer mental and physical health, poorer relationship quality with current partner, and higher levels of smoking and criminality.

"This study, based on a rare large probability sample, reveals far greater diversity in the experience of lesbian motherhood (and to a lesser extent, gay fatherhood) than has been previously acknowledged or understood," explains Regnerus. "The most significant story in this study is arguably that children appear most apt to succeed well as adults when they spend their entire childhood with their married mother and father, and especially when the parents remain married to the present day."

In a series of commentaries published in the same issue of Social Science Research, three family researchers share their views on both studies. David Eggebeen, Associate Professor of Human Development and Sociology at Pennsylvania State University, remarks, "Dr. Marks' paper, by turning a bright light on the shortcomings of previous work, challenges researchers to develop better data and conduct kinds of analyses that allow more confidence in generalizations. The Regnerus paper introduces a data set based on a national probability sample that has the potential to address some of Mark's criticisms. The analyses in the Regnerus paper are provocative but far from conclusive. These very preliminary findings should not detract from the real importance of this paper, the description of a new data set that offers significant advantages."

"Whether same-sex parenting causes the observed differences cannot be determined from Regnerus' descriptive analysis," cautions Professor Cynthia Osborne from the University of Texas at Austin. "Children of lesbian mothers might have lived in many different family structures and it is impossible to isolate the effects of living with a lesbian mother from experiencing divorce, remarriage, or living with a single parent. Or, it is quite possible, that the effect derives entirely from the stigma attached to such relationships and to the legal prohibitions that prevent same-sex couples from entering and maintaining 'normal relationships'."

In a final comment on Regnerus' research, Pennsylvania State University, sociologist and professor Paul Amato points out, "If growing up with gay and lesbian parents were catastrophic for children, even studies based on small convenience samples would have shown this by now

If differences exist between children with gay/lesbian and heterosexual parents, they are likely to be small or moderate in magnitude-perhaps comparable to those revealed in the research literature on children and divorce."