Research suggesting that children brought up by gay couples are happier than those with straight parents threatens to explode one of the chief arguments against equal rights for homosexuals.
According to the University of Melbourne, babies with same-sex parents have "significantly better" general health.
Babies brought up in all other relationships lag so far behind in the health stakes that researchers double-checked to see if there was a statistical error skewing the results.
The research may blow a big hole in the view that children thrive best when they have one man and one woman parent.
But researchers said there were no benefits to this family set-up. Children of heterosexual parents did not score better in criteria such as self-esteem or emotional behaviour compared with those of homosexual parents.
Children of same-sex couples also enjoyed stronger family cohesion.
Dr Simon Crouch of the university speculated that the reason for this could be steeped in some rather clichéd views about homosexuality. It seems talking about how you feel about things really could pay dividends for health.
''Because of the situation that same-sex families find themselves in, they are generally more willing to communicate and approach the issues that any child may face at school, like teasing or bullying," said Crouch.
''This fosters openness and means children tend to be more resilient. That would be our hypothesis.''
The findings echo research carried out by Cambridge University's Centre for Family Research, which found that children with homosexual parents suffered no disadvantages due to their parents' sexuality.
Prof Susan Golombok, director of the centre and report co-author, told the Daily Mail: "The anxieties about the potentially negative effects for children of being placed with gay fathers seem to be, from our study, unfounded."