In law school I worked on an interesting case as part of one of my classes. It was a real case, with a real defendant. And it involved a charge of 3rd degree criminal sexual conduct for engaging in sexual conduct with a mentally impaired person.
The alleged victim was not profoundly impaired or extremely mentally disabled. The alleged victim had been diagnosed with mental disabilities & had some difficulties in some areas, but for the most part seemed to function reasonably well.
In the case I worked on in law school, the alleged victim testified that she knew what sex was, she understood about STIs and about how pregnancy occurs, and that she hoped to have children of her own one day. She was not underage & she testified that she wanted to have sex with the defendant. Her parents testified that they had talked to her about sex & good touch & bad touch & assumed she'd eventually have a family of her own. When asked if he thought she was able to consent to sex, her father testified, "Well if she can't, then I can't because I've got the same mental disabilities that she does." The defendant was convicted.
Now, this particular charge requires that the State has to prove that the alleged victim's mental impairment prevents them from giving reasoned consent to sexual activity. The language of that implies that not all people with mental disabilities will be unable to give consent. Of course there are people who can't due to their mental disabilities, but not all. And in charging out this particular offense, I think it behooves the State to be cautious & really ensure that the alleged victim is actually a victim.
The problem with this particular charge is that it labels the alleged victim as permanently being unable to consent to sex, regardless of what they may want. If a defendant is convicted for having sex with an alleged victim & that alleged victim desires to have a partner or spouse one day and have children, they run the risk that their future partner or spouse will get charged with crim sex, bc the State has already decided that anyone who has sex with the alleged victim is taking advantage of a mentally disabled person. The State has already decided that the alleged victim is too mentally impaired to give reasoned consent to sexual activity. So, tough shit, alleged victim, but you don't ever get to have any kind of sexual contact for the rest of your life because the State has made the decision for you & you don't get to have that in your life.
Admittedly things gets murky in this area. People with mental disabilities are on a spectrum & some people are more or less functional than others with the same diagnoses. But just because it's murky doesn't mean it should be charged out. The result of this type of charge is that it can end up penalizing an alleged victim & taking away from that person the option to engage in one of the things other people get to enjoy. This type of charge is necessary to prevent people who are truly unable to consent due to their mental disabilities from being harmed. But when there is a person who is able to voice that they have wants & desires & understand the mechanics of sex & pregnancy & other aspects of being in a sexual relationship, does the State have the right to claim they can't give reasoned consent?