As a lesbian, every encounter I've had with males was non-consensual. Whether it was the creepy balding co-ed at college who cornered me in my dorm and dry-humped me and then told me not to tell anyone; the peeping tom who watched my girlfriend and I make out and then banged on the window yelling obscenities or the boy in high school who forced me to touch his penis in class repeatedly, all of this was against my will and after saying 'no' in various ways--sometimes while screaming in terror. I was also raped at 18 on a dark country road by a serial rapist who was later apprehended for another incident.  

None of this influenced my sexual orientation one whit. I've always been lesbian. It just solidified my belief that true consent is just an incidental bonus to most men.