The author of a US study which appeared to link an increased likelihood of negative life experiences in adults who grew up with a gay parent compared with those who grew up with married, straight parents has defended his study in the face of strong criticism.

The study, “How Different are the Adult Children of Parents Who Have Same-Sex Relationships? Findings from the New Family Structures Study”, has come under fire from several groups today.

The study compared the lives of adults who had grown up with a parent who had had a gay relationship, of any length, with those who had grown up with straight, married parents. The first group appeared to be more likely to be in therapy, have extra marital affairs and experience other negative outcomes in later life.

In the journal Social Science Research its author, Mark Regnerus, an associate professor of sociology at The University of Texas at Austin, said it was not possible to draw a causal link between a gay parent and such negative outcomes. He acknowledged the outcomes were more likely to be a result of the instability that having a gay parent in a less socially accepting time entailed.

He said organisations might try to use the findings “to press a political program. And I concur that that is not what data come prepared to do […] Implying causation here—to parental sexual orientation or anything else, for that matter—is a bridge too far.”

But the study has come under fire for introducing sexual orientation into what is seen as more of a comparison between children in unstable parenting environments with those in environments with stable, married parents.

Commentators have pointed out that gay couples are now able to marry and create more stable environments in many US states and that many of the children in the study would have experienced the break-up of their family when their parent realised they were gay, which could readily account for the negative outcomes experienced in later life.

The funding for the study, including $695,000 which Dr Regnerus received for the New Family Structures Study from the Witherspoon Institute, was also questioned.

Jennifer Chrisler, Executive Director of the Family Equality Council said: “Flawed methodology and misleading conclusions all driven by a right-wing ideology.

“That alone should raise doubts about the credibility of this author’s work. But on top of that, his paper doesn’t even measure what it claims to be measuring.”

Ms Chrisler added: “Everyday people in this country see real-life examples of the love, commitment and caring these parents provide to their children. These parents are raising their children to be kind to their friends and neighbors, support their communities and uphold American values. One biased paper cannot undo the truth nor demean the value of these families.”

Human Rights Campaign President Chad Griffin said: “Because of its serious flaws, this so-called study doesn’t match 30 years of scientific research that shows overwhelmingly that children raised by parents who are LGBT do equally as well as their counterparts raised by heterosexual parents.”

Freedom to Marry President Evan Wolfson said: “The two million kids being raised by 1 million gay parents in this country are doing great, and would do even better if their parents didn’t have to deal with legal discrimination such as the denial of the freedom to marry, and ongoing attacks such as this kind of pseudo-scientific misinformation and the disinformation agenda that’s funding it.”

A press release from Freedom to Marry said the paper was “fundamentally flawed and intentionally misleading. It doesn’t even measure what it claims to be measuring. Most of the children examined in the paper were not being raised by parents in a committed same-sex relationship—whereas the other children in the study were being raised in two-parent homes with straight parents.

“Given its fundamental flaws and ideological agenda, it’s not surprising that the paper doesn’t match the 30 years of solid scientific research on gay and lesbian parents and families. That research has been reviewed by child welfare organizations like the Child Welfare League of America, the National Adoption Center, the National Association of Social Workers and others whose only priority is the health and welfare of children and that research has led them to strongly support adoption by lesbian and gay parents.”

GLAAD President Herndon Graddick added, “A growing majority of Americans today already realize the harms this kind of junk science inflicts on loving families. If the media decides that this paper is worth covering, journalists have a responsibility to inform their audiences about the serious and glaring flaws in its methodology, and about the biased views of its author and funders.”

In response to these criticisms, Dr Regnerus told PinkNews.co.uk today: “Ms. Chrisler’s statements, while fine, are anecdotal, remarks about her personal observation of the world around her. What the published article features is data of the highest-quality: a population-based, random sample of 18-39-year-olds in America. It is an improvement upon the sampling strategies of much research that has come before it. If critics prefer the conclusions of “30 years of research” based largely on non-probability samples, I understand. But the sampling flaws are more pronounced in previous studies, not mine.

“I am neither well-known for anything, nor am I right-wing. Right-wing scholars vote Republican. I have never voted for a Republican presidential candidate in my life. Not that that’s relevant here, but critics have attempted to make it relevant. I am Catholic, but so are 1 billion other people. There’s no Catholic way of drawing a sample or of running regression models. Religion and politics do not belong in this. Scientific rigor does, and despite attempts to undermine me and the peer-review process, that is what this study exhibits.

“The study went through a normal, “blind” peer-review process at a respectable sociology journal, whose editor elected to request three comments from other family scholars, including the current president of the National Council on Family Relations, the largest academic body of family scholars in America. All three affirm the data’s quality, while offering appropriate qualifications that I affirmed in my response to them.

“Yes, the study was underwritten by the Witherspoon Institute and Bradley Foundation, each of whom had nothing to do with the data collection process, decisions, analyses, interpretations, publications, etc. They invested in what is now the highest-quality dataset of its sort, one which has several natural limitations noted in the study itself, including the fact that this is about 18-39-year-olds, is not a study of parental sexual orientation per se, and is nowhere claimed to be “causal” in its assessments. Indeed I have been quite guarded in my interpretations of the data, far more guarded than critics have been of me.

“On the last criticism, concerning inappropriate grouping of respondents whose mothers had a same-sex relationship. There are only two cases out of 175 such respondents in which the respondent detailed that he/she lived with their mother and her partner for all 18 years of their childhood. Two more reported living together with them for 15 years, and two more for 13 years. Such small numbers of cases–six here–are not ample to evaluate statistically. Suffice it to say, in a nationally-representative sample of young adults, there were very few who exhibited sustained stability. I wish there were more to report on, but after asking 15,058 people about their parents, that is what we found in a population-based sample.

“Finally, the study states, and I reiterate here, that it’s not a study of parenting or a study of parental sexual orientation. I understand that message gets lost in the emotions surrounding this, but I can only defend what I’ve written, not what people perceive about it.”