I have never had a masturbation fantasy involving a woman alone, or several women for that matter. I was able to explain that to myself by thinking that would be "dirty," to the point I remember a guy showing a Playboy centerfold during 9th grade English, and I turned away. Not much after that I can remember seeing a female friend's Playgirl, and being impressed and probably turned on.
Sexuality does probably follow a continuum - after all, according to Lady Sally monosexuality is the primary hangup of the 20th century. [sorry, couldn't find the book for the exact quote]. If I had a choice between getting married to a woman [having ejaculations caused by the physical act of sex rather than desire] and being stoned to death, I would get married.
What all this leads to is that while the "reparative" therapy might be able to take someone who is bisexual and make him so guiltridden that he never wants to have sex with a man, I don't think there is anything that could happen that could make me have sexual desires towards women rather than men.
By the way, I don't think 10% of the male population is gay, either.