Gays can't become ungay?

Question for the 4channer community: Do you think it's entirely NOT possible at all, not even in the least to be aroused by a women if you are gay? Obviously not all "gays" are exclusively attracted to other men, they do have some physical interest in women, correct? (Being "bi"). A study I came across once suggested that most men (and women) have a partial attraction to both sexes, by measuring blood flow to parts of their body when exposed to certain scenes and or images.

So if many men and women are atrracted to both, does that mean that there are some men that are 100% incapable of getting or maintaining an erection with a female, and actually having sex with them? The reason I ask is because if even a few men are like that, how could it possibly be claimed that sexual preference is based on emotional factors and growth as well as your physical make up? I personally believe that your body tells you what you wish to mate with. How else would you explain the reaction of blood flowing to the right parts and hormones that react to certain stimuli? You don't choose to have an erection at all times, your body does it for you.

tl;dr version: Is there even ONE man on earth who can't keep a boner with a girl or have sex with her?

>>8
Actually magicalgirl, no, I don't get aroused when and if I get touched, I go "what the fuck who touched me, why, and how hard do they desire a quick and painful death?" Most likely I will have already made movements to make sure no further touching goes on until I have decided to start the battle scene or not.

But that's just my true physiological response, I know for sure that I cannot do anything else, like be turned on just because something touched me. I could try, but why the hell would I want THAT.