As for false alagations of rape etc from female victims; it varies from jurisdiction why there is reluctance to prosecute but a common theme is they do not want to deter "legitimate" victims from coming forward.
Yep, that was the excuse I always heard too. I remember one of the last cases I worked all too well. The story was some guy raped a girl at a party. Based on her statement, and forensic evidence of sexual intercourse, a grand jury indicted the guy and we arrested him. He was 19, couldn't make bail, and was stuck in the county jail for months awaiting trial. As part of getting ready for trial, we did a follow-up interview with the girl, and a lot of her statement changed, which made us suspicious. When we started pointing out how her story had changed, she got upset and finally said "If you don't believe me you can ask X and Y (her friends) because they were there!" This came as a shock to us because we had been told there were no witnesses! Then she immediately retracted her statement about X and Y being there.
We detained this little POS while we called X and Y and it turned out they were there, and they both reported a rape had taken place, but she had raped the guy! The guy had been drunk and half passed out on a bed at a party, and the girl had taken off his clothes and had sex with him. When we confronted her with the statements from her friends, she copped to the whole deal. She said she had had sex with the guy, got worried that she might have gotten pregnant, and made up the whole rape story
in case she did.... not because she did get pregnant, but just in case she did!
So the guy gets released after spending three months in jail and losing a good job, will always have an arrest record for sexual battery and rape, and he's in the MD and Federal sex offender databases for the rest of his life. And the girl? Nothing. We were told to not even bother filing any charges against her because "some will say that unless a woman can prove 100% she was raped she might not come forward." I've dealt with some rape cases, and I think it's an insult to women to make this case. They think less of the women who do this crap than I do.
Victims of rape tend to fall into two categories: those who want to hide that they were raped and those who want to cut the nuts off the guy who raped them. There's nothing that will encourage or discourage the first group from reporting a rape because they will not do it. As for the second group, there is nothing that will discourage them.