It is my opinion that they should be able to do anything that straight people can do. The fact that we are restricting them from getting married reminds me to much of the restrictions we placed upon women and blacks which most people would agree were terrible. I would also like to point out that I am not gay, I just believe in the freedom of the people. Feel free to post the opposing side of this as always.
Djkgb, stop trying to look at sexuality as something so complicated. It isn't. So, do some introspection, okay?
I bet you are not unsure about the sex you are attracted to. I also bet you are not unsure about the type of person you are attracted to, either. It is the same for most everyone, regardless of someone's sexuality.
Now, also keep in mind that sexuality is not a choice. I, again, bet you did not wake up one day and decide to be heterosexual (assuming you are). You just are the way you are.
Homosexuality isn't something you suddenly 'catch' - I'm quite sure that (on the whole) homosexuals know which sex they like - hence the term 'homosexual' and not 'bisexual' in the title of the topic. From the sexual POV it really is as simple as
Heterosexual - Guy+Girl Homosexual - Guy+Guy or Girl+Girl
That's just the two basic 'norms' when talking about sexuality but you get the idea.