It's happened in the past, both in conversation and in past blog posts such as this one, that I have played with the idea that one's sexual orientation may be fluid, rather than a static state. That is to say, that I don't necessarily agree with the idea that one's orientation is decided at birth.
Keep in mind, I know I'm speaking as a woman who identifies as straight, thus far (in keeping with where I am going with this), so I will try to keep my privilege in check and not make assumptions.
This is where people either respond with A) "That's ludicrous! You can't choose whether to be gay or straight!" or B) "Aha! So you agree, it IS a choice!"
No. That's not what I'm saying. If I say one's orientation can change, that doesn't mean I'm saying it's a choice. It's based on the difference between the following two adjectives
Changing: Something that is capable of change.
Changeable: Something that can be changed by force or manipulation.
So while I would agree that one's sexuality is unchangeable (that is to say, you cannot force change upon it - you can't 'cure' someone of being gay/straight, nor can someone say 'I've decided not to be gay/straight today') I would question the idea that it is a completely static birth-to-death state of being.