Honestly, taking away the rights from a human being to have children is as bad as those people who try to outlaw abortion, if not worse.
Just let people friggin do what they want with their bodies. Ok from an efficient way of looking.. simply outlawing children would be the easiest solution ever... But easy isn't always best.
It is in our instincts to have children. Few people do not want children at all, and even though Im one of them, I've talked enough to my sister to know where people who want kids are coming from. Some people crave to have children so much, that being forced not to have one is just horrible. Think about how depressed the population would get.. What tension this would create. I can certainly imagine this wouldn't fly well with the majority, and i can also imagine a lot of riots taking place. Outlawing a thing so carnal to our nature is just .. retarded. Sorry.. I mean idealistically it would be a splendid idea. I wouldn't mind as I don't want kids. But in the real world, things are more complicated than that. And why discuss ideals when they lead to nowhere anyway?
Anyway something like this has already happened... In China!
http://geography.about.com/od/popula...a/onechild.htm
The one-child only policy...I don't know what to think of it but at least that makes more sense than allowing no children at all.