No, they are not born gay, but don't expect this information to be widely circulated.
I'm straight (and proud of it!), and I have been straight since I was born.
It seems normal to me that a woman loves a man.
I don't know if it's just me, but whenever people told me they were gay or lesbian, I'd think it was so strange and not at all right. It just didn't feel normal to me.
I'm glad we have an argument for us straight people. And believe me, we are not the strange ones.