Heres the thing:
No one is 100% straight opr gay ( no matter what they say ) The data concerning prenatal hormones is interesting in that it shows us that we can be predisposed from birth to a certain orientation.
Lets say three people are born this way
Person A is predisposed 70% homosexual 30% straight
Person B is predisposed 50/50
Person C is predisposed 30% homosexual 70% straight.
Predisposition does not decide on the persons eventual sexual orientation. That comes from two other factors: Enviornment and finally choice.
Now some people will object to the choice factor but let me explain. One has to accept what they are in order to live their lives. In that sense, choice is a factor.
I think the reason theres such a strong debate on the subject is that there isnt a single cause but a combination of factors that lead to sexual orientation, both straight and homosexual.
I have actually heard of this theory before, and another one similar to it in that sexuality "fluxuates" as a life progresses.
I can safely say that there have only been a couple of instances in my life to where I was (a little) aroused at the female form. So, speaking on a personal level, I can see how this theory could be believable/valid, but... what do you have to say about those who claim to have never been attracted to women before? That they're lying or...
EDIT: Forgot this: Again, I am sorry to repeat myself, but it is not about whether we accept what we are and make a choice (as you put it), but what we are dealt with in terms of the orientation itself. I did not choose to be attracted to guys. I just am. I
choose to date guys because my attraction to women is so minute and rare that it's almost nonexistent.