It would be interesting to see how that correlates to other factors, such as lifelong fidelity.Excellent point. In fact, the vast majority of "gay father" or "lesbian mother" respondents were the children of a straight marriage that ended when the mother or father had a homosexual fling and then abandoned the family. This calls into question what effect this study is actually measuring.
It's not news that kids from broken homes don't fare well.
I saw a scenario like this: mom and dad divorce, then dad (and pre-teen daughter) form a new household with dad's boyfriend. Talk about being set up for suffering. I feel sorry for the kids --- well, for everyone in these messed-up situations.