WASHINGTON — During last week's Supreme Court arguments on gay marriage, Justice Antonin Scalia asserted that "there's considerable disagreement" among experts over whether "raising a child in a single-sex family is harmful or not." Two other justices agreed that gay parenting was a new and uncertain development.
Those comments startled child development experts as well as advocates of gay marriage, because there is considerable research showing children of gay parents do not have more problems than others.
"This is not a new phenomenon. We have 30 or 40 years of studies, and there has been no hint of a problem," said Dr. Ellen C. Perrin, a professor of pediatrics at the Floating Hospital for Children at Tufts Medical Center.
"There is a fundamental, scholarly consensus that children raised by same-sex couples do just fine," said Stanford sociologist Michael J. Rosenfeld.
Perrin led a committee that examined research on gay parents and their children for the American Academy of Pediatrics. Its report in March, just before the court arguments, concluded that "children and adolescents who grow up with gay or lesbian parents fare as well in emotional, cognitive, social and sexual functioning as do children whose parents are heterosexual."
While children benefit from a stable home with two parents, she said, the gender of the parents does not appear to make a difference.
The issue arose in the Supreme Court when the justices were arguing over whether there was a valid reason for barring same-sex marriage. Scalia cited the possible harm to children who were adopted by same-sex couples. Justices Anthony M. Kennedy and Samuel A. Alito Jr. said it might be wise to move slowly because gay parenting was still new.
"We have five years of information to weigh against 2,000 years of history," Kennedy said.
Evan Wolfson, president of Freedom to Marry, said the questions from Scalia and other justices ignored the testimony in the initial trial of Proposition 8, California's 2008 ban on same-sex marriage.
"That was the most astonishing aspect of the entire two days [of Supreme Court arguments], given the trial record in this case," he said. "There was an enormous amount of evidence put in the record that gay parents are fit and loving and their children are doing well."
Michael Lamb, a developmental psychologist at Cambridge University, testified at the Proposition 8 trial that research had shown children of same-sex parents were as likely to be well-adjusted as those of heterosexual parents. Nearly 40,000 children in California are being raised by gay couples.
Kate Kendell, executive director of the National Center for Lesbian Rights, said she was surprised to hear Scalia speak of adoptions by same-sex couples as an open question. No state forbids adoptions based on sexual orientation, she said. "That was another moment when I felt like it was 2003 instead of 2013," she said.
The research on gay parents began with small groups. Since the mid-1980s, Dr. Nanette Gartrell, a San Francisco psychiatrist, has tracked children who were born to lesbian couples through artificial insemination. As they grew up, these children were compared with others in similar, middle-class families. She said the children being raised by lesbian parents "had fewer behavioral problems, were succeeding academically and were well-adjusted. And they greatly admired their mothers," said Gartrell, now a visiting scholar at the Williams Institute at UCLA.
Not all of the academic experts find this research convincing.
Douglas W. Allen, a Canadian economist, says the many positive research reports on gay parents and their children were questionable. "The samples are small and biased. The people are self-selected," he said. "If you start with a biased sample, you can't make a statement about the population as a whole."
He published data from a Canadian census survey in 2006 that found children with lesbian or gay parents were less likely to graduate from high school.
Perrin, the Tufts professor, said the research studies also made the case for gay marriage. "Marriage helps to create stability and permanence. And stability is good for children," she said. "If a child is lucky enough to have two capable and loving parents who choose to create a bond of marriage, it is surely in the best interest of that child to allow them to marry."
Researchers on both sides of the issue say it is often hard to make statistical comparisons of children raised by same-sex parents to those raised by heterosexual couples. Children raised by gay men are usually adopted, and some may have been abandoned by their parents. Looking just at statistics would show these children were more likely to have problems, regardless of who raises them.
"We have always known family disruption is difficult for kids," said Rosenfeld, the Stanford sociologist. "But if you control for things like income and family disruption, the studies show that kids raised by same-sex couples are not at a disadvantage. We have pretty good data, and it shows these kids are doing well."
Savage reported from the Washington Bureau.