I have mixed feelings here. I don't know that sex if you're infected with something like the AIDS virus should be absolutely prohibitted. I'm not even sure that you should be forced to volunteer the information automatically. However, if somebody asks you and you lie about it, I think that ought to be criminalized, perhaps even to the charge of murder if you infect somebody with AIDS (a difficult thing to prove). Reckless endangerment of the life, health, and welfare of another seems reasonable, not to mention fraud. But these laws would have to be crafted with extreme care so as not to be overbroad. It's an area of privacy where the government should have very little presence. The slope can get very slippery.

Many states prohibit sex when you knowingly have a sexually transmitted disease.