Being bisexual I would like to say, that I believe that most of the components of our personality can be affected by experiences in childhood. Like how much risk we are willing to take, how much arguing we can stand in a relationship before leaving, our choise of career and so on. And also sexual orientation and preferences. But just like the other stuff in our personalities are affected by so many things you can't separate on factor, I believe it is the same with the sexuality part.
You can rarely say "I need a lot of risktaking because I had a boring childhood". Because the risktaking trait is caused by many different things and you can't be sure of one cause.
Then of course, the risk taking trait will not be examined like this until it is percieved as a problem. Then you ask yourself why do I need these risks, trying to understand to change. But you could just as easily ask yourself why am I so craven, if that would be the problem.
So my input in this is, who decided that homosexuality/bisexuality is the problem that must have been caused? It could just as well have been heterosexuality that was caused by the abuse? But since heterosexuality is the norm it is not percieved as a problem to be hetero.
Just saying. Maybe we are discussing this from the wrong angle.