Vigil & Lilith,
A strong juxtaposition of posts!
I am, as I’m sure you are aware, deeply suspicious of preemptive government efforts on my behalf.
That being said, sex offenders, such as rapists, pedophiles, and even exhibitionists, commit crimes that put fear into the general public and pose a threat to people that live in their neighborhoods. They are a clear and present danger to the population, and particularly to the children.
Chemical castration is an effective technique . When the testosterone levels of men convicted of sex crimes is lowered, recidivism rates fall from greater than 45% to less than 5%.
http://www.crime-times.org/95d/w95dp6.htm
Their sexual fantasies are lessened as a result of the reduction of testosterone levels. It is an "offender friendly" way of reducing sexual violence. It is also cost effective. Some estimate that the injections cost $21 a day, while incarceration costs twice that. This is not to say that the cost of the sanction (imprisonment vs. chemical castration) should determine the sanction, but it is a factor that should be considered.
Finally, the treatment is not permanent, so if the conviction is reversed on appeal or for any other reason, the convicted can return to his normal, if that is the appropriate term, functioning.
http://www.biomedcentral.com/1471-2407/1/18
Still, there are ethical issues involved. Physicians should avoid administering a drug to a patient if that drug is not clearly beneficial to that patient. This drug would be administered for the benefit of other people, rather than the patient himself.
Historically, the Federal government is rather liberal, insofar as it has had a limited range of direct involvement with its citizens. This has changed of late, but most of the draconian legislation here is dished out by the states, which reflect the enormous range of acceptable or appropriate behavior in this very variegated nation.