IANAL. I live in Michigan, so I just looked up the Michigan law on statutory rape. Interestingly enough, the law says, "(1) A person is guilty of criminal sexual conduct in the first degree if he or she engages in sexual penetration with another person and if any of the following circumstances exists: (a) That other person is under 13 years of age. (b) That other person is at least 13 but less than 16 years of age and any of the following: ..." and goes on to list various conditions.
So by a strict reading of the text of the law, it is not necessary for the accused person to have engaged in sex with the underage person voluntarily, just that they engaged in sex.
That said, I would be very, very surprised if any court in the US listened for 10 seconds to an argument that a rape victim should be prosecuted for statutory rape because the rapist was underage. Our courts can be pretty stupid, but I don't think they're THAT stupid. I've never heard of such a case. Of course I don't study every reported case of rape in the country. On the other hand, you'd think if there WAS such a case, something that outrageous would likely make national news.
There might be a realistic scenario here where an underage person rapes an older person, and then claims that he (or she) was the victim. Like, "She says I forced her at gunpoint? But I don't even own a gun! She told me that if I didn't have sex with her she'd give me a failing grade in her math class ..." etc. But then the argument would be over what really happened, not a blind application of statutory rape laws.
Addendum several years later:
Note that the linked paper is spinning a hypothetical case based on a very literal interpretation of a statute. Once could spin many such insane hypotheticals. Like, suppose a maniac with a gun takes hostages. At some point he gets tired and puts down the gun, and one of the hostages grabs the gun. Can the hostage be prosecuted for theft? After all, he took the maniac's gun, i.e. he took someone else's property without permission. This might technically meet a definition of theft but I sincerely doubt a prosecutor would actually charge the person.
Etc. I'm sure if you went through law books you could come up with many other such hypothetical technicalities.
That said, sometimes people in authority do indeed impose stupid rules. When my kids were in school, the school had a policy that if two students were in a fight, both would be suspended, regardless of who started the fight. So ... if a student is just walking down the hall minding his own business, and some bully walks up to him and punches him in the face for no reason, both the bully and the victim will be suspended. My guess is that they made this rule because sometimes it is difficult to figure out who really started the fight and what it was all about. Personally I thought it was a stupid and totally unjust rule. (Lest you wonder, it never affected any of my children. But.)