A lot of the arguments saying that you can't be born Gay seem to invoke the "It's useless for evolution so it can't exist" argument. So I'm just gonna make this little post here:

We have an appendix, and some people have sickle cell disease. One of those is unnecessary now, but it's still there. The other one is a potentially fatal condition, and it still exists. I do t have a degree or anything, but I'm pretty sure that evolution isn't everything that serves no purpose being eliminated. 

Besides, mutations exist. They're, you know, the reason we aren't amoebas.