Though I agree that it should not matter how we are oriented, whether from birth or from choice, and that our access to equal rights should not be contingent on us being 'born this way,' I do believe people are born gay for this reason. If it was a choice I'm sure people would opt out. There choice to do so but statistics say people do have a choice and some peoples choice would have not chosen this for their own reasons.
I do not think being gay is as simple as a choice, but I believe that when you're a child you are still trying to form connections and gather facts about the world. During this time you form your basic fundamental traits, although some genes do make some traits prominent than others, but you form what you think is socially acceptable, and you aren't even close to figuring things out about sexuality. I believe that during this time when you are so open to what you're parents tell you and what facts you are gathering, later in life you may develop certain personality traits that may make you homosexual, due to the basic fundamental connections you have formed as a child.