Do you like crack babies?
Permanantly retarded children with serious emotional and learning difficulties that are born addicted to crack. They cost society, for the most part, a fairly large amount of money in social security payments, in prison costs, and in helping them (and often their victims) to put their lives back together.
All because their parents were addicts.
I'm not saying you HAVE to get sterilized - just like you don't HAVE to take drugs. Just if you want cheap, easily availible drugs, you don't get children. If you want to take drugs, you don't have to hide it from the rest of the world - we'll just help you find somewhere you can do it without hurting anybody else.
THAT'S the idea.
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche