Sterilization is a necessary treatment for pedophiles and other sexual predators. If a rapist has shown extreme sexual perversion, sometimes the best punishment is for this person to lose the use of their sexual organs. This is the only way to protect innocent members of society. We should be touch on sexual criminals.
If someone is smoking half a pound of crack or meth, then they shouldn't be having any kids. This would actually benefit the mother since if she is selling her body for the hard drugs, then she wont have to pay for birth control. As for sex offenders, they should not be able to raise kids with that they have done.
Regardless of how heinous of a crime someone does or how bad or simply annoying someone is, that does not give someone else or the state the right to sterilize them. A system that has authority to sterilize it's citizens could easily abuse it for evil purposes of eliminating minorities, disabled people or people who oppose it. Nor should for any other reasons should people be inconsequentially sterilized.