Women who rape? Why are they not punished?

10% of rapes occur with a woman attacking a man. Not going to go into man to man rapes. But police expect there are many more than that considering men do not report it because they do not want to be perceived as weak. 2.78 million men in the U.S. have been victims of sexual assault or rape. This is quite alarming and yet most courts won't punish a woman for raping a man like they would for a man raping a woman. And obviously I have heard stories where men say oh yeah I wouldn't mind it, but in reality woman-man rape usually involves a mans genitals being mutilated in the process, again I will not go into detail, or a woman using foreign objects on the man. Why are woman not punished for their wrong doing? Hopefully this will change in the future. Also its not just happening in the U.S., in Zimbabwe women ritually gang rape men.