"The knowledge and prudence of the poor themselves, are absolutely the only means by which any general and permanent improvement in their condition can be effected." - Thomas Malthus
As far as dissuading and preventing people from becoming parents too soon, I think that can be done much in the same way education about safe sex has had a great deal of success in preventing the spread of STDs. I can't really speak a lot on what specific solutions I would advocate because I just haven't done a lot of research on the issue. Regardless, I think the best solution is to help people make the right choices rather than let government decide who does and doesn't have kids.
"It ain't what they call you, it's what you answer to." - W. C. Fields
"God is the name by which I designate all things which cross my path violently and recklessly, all things which alter my plans and intentions, and change the course of my life, for better or for worse."
-C G Jung
So people are actually advocating making the entire population sterile until such a time that the government deems them "acceptable" to have children? Because of SOME irresponsible people who make up maybe 15% of the entire population? Hmmmm.