For the same reason that you can't sell your baby, or your body, or other body parts. You have AUTONOMY over your body to do what you want with it on a volunteer basis. So you can give a kidney or part of a liver to someone, or you can give your baby up for adoption. You can donate your aborted fetus to science. But you can't sell any of those things. There are laws governing and limiting commerce because they involve more than just yourself and your own body. Abortion is not a form of commerce, you are not selling the aborted fetus. And yes, you can get an elective hysterectomy, it's perfectly legal. However, it involves another person--a doctor. And the law cannot compel the doctor to perform an ELECTIVE surgery. So while it's your right to have the surgery, it's also the doctor's right to decide when and on whom and why to perform ELECTIVE surgery. And I'm guessing you can't find any docs to perform an elective hysterectomy on you because your reasoning for wanting it is flawed. Respectable docs are not too happy to remove healthy organs at the whim of their patients, when a minor, less invasive procedure will do.