If you're going to have kids that you have no means of supporting, why not give them up for adoption?

It's all these poor single mothers in their teens and 20s with little means to support their *unwanted* children who feel "obligated" to keep their kids and put a struggle on them and their kids. If the mother can't afford to look after the baby, and doesn't want it, why not have the child adopted by someone who actually wants and can afford to look after it?