Same-sex parenting has been a contentious issue since the 1980s, but the struggle for marriage equality has brought the issue back to the forefront of public debate. Scientifically speaking, though, there’s not much of a debate. No peer-reviewed study has ever found that gay parents in stable relationships are a disadvantage to their kids.

The latest study, by an international team of researchers from the U.S. and the Netherlands, looked at 190 intact families (95 different-sex, 95 female same-sex parents) with at least one child between the age of 6 and 17. They looked at the children’s general health, emotional difficulties, coping behavior, and learning behavior, and discovered no differences between children raised by same-sex or different-sex parents.

This finding, published in the Journal of Developmental & Behavioral Pediatrics, is obviously not a surprising discovery. Including this latest one, there are 74 scientifically peer-reviewed and published studies showing that gay and bisexual parents in stable same-sex relationships don’t disadvantage their children. The four claiming the opposite have been either debunked or have never been peer-reviewed.

This study was based on the 2011-2012 National Survey of Children’s Health, and the families were selected from the 95,677 households who completed interviews. Initial analysis revealed 139 female and 17 male same-sex couples, but these were reduced to 106 families (95 female, 11 men). This was because the researchers wanted families that had their children since infancy, as divorce and parental separation could affect the development of a child.

Having such a small sample for male same-sex couples, the researchers focused solely on female same-sex couples and constructed a control sample of different sex parents from the general population based on the age, education, U.S. birth status, and current geographic location of the parents, as well as the age, sex, race/ethnicity, and U.S. birth status of the children. This methodology guarantees the crucial variable in the study to be just the sexual orientation of the parent.

While the study didn’t show any differences in the health and development of children, it did show an increased level of parental stress. The National Survey did not have specific enough questions to pinpoint the cause of the stress, but based on previous studies, the researchers suggest that same-sex parents “have concerns about rearing their children in a homophobic society and feel more pressure to justify the quality of their parenting than their heterosexual counterparts.”

[H/T: Slate]