Here's a classic article from the Health section of the New York Times tonight:
Gay Unions Shed Light on Gender in Marriage
By TARA PARKER-POPE
For insights into healthy marriages, social scientists are looking in an unexpected place.
A growing body of evidence shows that same-sex couples have a great deal to teach everyone else about marriage and relationships. Most studies show surprisingly few differences between committed gay couples and committed straight couples, but the differences that do emerge have shed light on the kinds of conflicts that can endanger heterosexual relationships.
The findings offer hope that some of the most vexing problems are not necessarily entrenched in deep-rooted biological differences between men and women. And that, in turn, offers hope that the problems can be solved. ...
Personally, my motto is vive le deep-rooted biological differences between men and women.
And here's a stunning finding about same-sex "marriages:" partners who aren't of different sexes don't exhibit stereotypical sex differences!
Notably, same-sex relationships, whether between men or women, were far more egalitarian than heterosexual ones. In heterosexual couples, women did far more of the housework; men were more likely to have the financial responsibility; and men were more likely to initiate sex, while women were more likely to refuse it or to start a conversation about problems in the relationship.