How come some people are allowed to breed?

Seriously, It's just a shame. I am curious how some people make it as far as they do, but after losing a child to state custody and or just plain being neglectful. why do they have more? It's frustrating. I think they should check their options and do whats best for the unborn child. These woman should get a card, bracelet or a tag that doesn't allow them to conceive. Oh my heart hurts just thinking about it