I would say there's nothing wrong with gay parenting. Studies have shown that on the one hand, children of gays are slightly more likely to experiment sexually, they are loads more likely to be safe about it.
Regardless, I see nothing wrong with my daughter. Granted, she's a scant six years, she's doing just fine. While I definitely worry a bit about kids who are anti-gay in her school, she happens to be in a pretty liberal school district, and there are plenty of other kids with gay parents in her school.
In all reality, people either make good or shitty parents. I think that straights are more likely to be shitty parents, primarily because of the accident factor. Gays can't accidentally get pregnant, they have to choose. And I believe that that says a lot for how well they will care for their children.