I'm not sure about the adopted part, but we now have quite a few studies on adults raised by lesbians. You might want to click on the link provided to take a look at some of them.
I think the biggest problem is people like Rosie O'Donnell and Ellen they make the head lines and give gay people a bad name I would never allow crack pots like them to have children not because they are gay but because they are nuts looking for attention. Unfortunately this is what people see and they associate it with being gay. Where I live this is not an issue gay people don't act any different than straight people (no gay pride no straight pride parades we are all just people) and they are perfectly accepted, so, I kind of think this is more of an American issue.