Is causing another person injury a criminal act? Of course it is. If I strike another person in the side of the head with a crowbar and they go to the hospital, there would be no debate as to whether I had committed a crime.
Why, then, is there debate over the criminal nature of a person who knows they have a sexually transmitted disease giving that disease to their partner?
There are people in intimate relations where one or both have sexually transmitted diseases, and they both know about it. In those cases, both partners are accepting the risk of their activity, and the possibility that the disease will be spread to the other. There is no crime in such cases should the infected partner transmit their disease to the uninfected. If you ask me to punch you in the stomach, and I punch you in the stomach, and it hurts, I haven’t committed a crime. You would not have the recourse of going to the legal authorities and complaining about what I had done after you asked me to do it.
The criminal aspect comes from the act of intentionally, or even recklessly, injuring another person by giving them a disease. If a person knows they have AIDS, or chlamydia, or syphilis, or any other of a host of diseases that are spread sexually, and that person has sex with another person without telling the person the risk they run, they are committing a form of assault against their partner. Their intent may not be to pass the disease to their partner; they may be taking every precaution from condoms to medication. However, they are exposing their partner to a risk of infection just the same. Let’s face it, sex gets messy sometimes and you can’t prepare for, or account for, everything that might happen. Exposing another person to risk of harm by your actions, is a criminal act.
I would take it one step further, in fact. I would not only say that causing an infection to a person should be a crime. I would say that just exposing another person to the chance of being infected should be a crime. Again, I’m not talking about consenting relationships with an infected partner where the risks are known. I mean to say, that if person A has herpes (for example), and has sex with person B without telling person B about the infection, person A has exposed person B to the risk of being harmed. If it is discovered person A acted in this way, with reckless disregard for the safety of their sexual partner, then person A should be held criminally liable and charged with a crime. A lesser crime than if they had actually infected person B, of course. It is the difference between an assault committed, and attempted assault, but both are still criminal acts.
Pushing someone out into traffic. Hitting them upside the head with a crowbar. Stabbing someone with a knife. All these things can cause injury, and often serious injury, to the victim, and that is why our society has labeled them as “crimes” and enacted laws to prevent and punish such activity. Why would we make an exception for any other kind of activity that could cause injury, often serious injury, to a person?