Children growing up with gay or lesbian parents progress through school just about as well as their classmates with straight parents, according to a study believed to be the first large-scale examination of the well-being of children with same-sex parents.

"The difference in outcomes varies only a little bit by family structure. The really important things are parental income and education; the parents' social class is the big determining factor," says Michael Rosenfeld, an associate professor of sociology at Stanford University. "The question is: what about family structure? The answer seems to be — at least in the case of same-sex couples — that it doesn't matter.

Rosenfeld used U.S. census data from 2000, the most recent year for which that type of information is available, to assess how children in different family types fared in school, using their ages and grade levels to figure out how many of them had been left behind a grade.

"When children are living in a chaotic home situation, they're much more likely to not be making progress at school and, therefore, to be held back," Rosenfeld says. "Children's progress through school is actually a reasonable proxy for the health of the home environment."

His sample included nearly 613,000 children in grades 1-8 living with two married heterosexual parents and 3,500 living with same-sex parents.

He found that 6.8 per cent of children with straight, married parents had been left behind, compared with 9.5 per cent of those whose parents were lesbians and 9.7 per cent of those whose parents were two cohabiting gay men. By comparison, about 11 per cent of children living with separated, divorced or widowed mothers or fathers were held back, along with a similar proportion of those with common-law heterosexual parents.

However, the slight academic advantage of children with married heterosexual parents is due primarily to socioeconomic factors, Rosenfeld found, and once those differences were controlled to compare children with the same racial background, parental income and education, the differences almost disappeared.

"The biggest determinants of children's educational progress are not parental gender but the things we always know have mattered, which is parental education and parental income," says Rosenfeld.

The research was published in a recent issue of the journal Demography.

Straight, married parents tend to have higher incomes and more education than their same-sex counterparts or those with different relationship status, he notes. They are also more likely to be white.

Cherie MacLeod, executive director of PFLAG Canada, says it's "absolutely in no way surprising" to her that children of same-sex couples fare just as well as those with straight parents.

In her experience, same-sex parents tend to be highly involved in their children's lives and schools because they're hyper-vigilant about ensuring their children aren't being teased or bullied because of their parents' sexual orientation. A 2008 study from the Gay, Lesbian and Straight Education Network demonstrated just that, finding that same-sex parents were more likely to attend parent-teacher conferences and volunteer at their children's schools than their straight counterparts.

"I look forward to the day when we're not constantly turning to researchers to justify the value and the validity of same-sex couples and families that are headed by same-sex couples in society," MacLeod says.

The study results are no surprise, either, to Stacy Green. He and his partner Adam Muhly have been together for 10 years, and Green's 17-year-old son lives with them. His 15-year-old daughter and 12-year-old son also visit regularly. He believes most schools in Canada have students growing up with two moms or two dads, and his two oldest children each has a couple of friends with same-sex parents, for whom they act as sounding boards and support systems.

"As it normalizes, as kids see more and more of that in school, I think that will eventually mean, with my fingers crossed, that we'll never have to write stories about it again," Green says. "We always talk about how kids need a mother and a father. Well, they don't need a mother and a father, they need balance. They need one parent they can confide in when they need to, they need another parent to go to for stern advice when they need it."