To address your last point first; I've long advocated for massively overhauling and improving our foster system. It's a broken, shattered mess.
As far as the rest goes, everyone has the right to life and a future (living freely, pursuit of happiness, etc. Whatever you want to call it, it necessitates being able to control your own destiny). How is permanently taking that away from someone, whose humanity we ignore and strip away purely because they're less developed than us, somehow LESS harmful than supporting a woman through a pregnancy so we can help her through the ordeal AND protect the new life? It's not a romantic notion; it's reality. Nothing but age separates a fertilized egg from an Olympic athlete. Arguing that rights should be ignored because of age is like arguing that rights should be ignored because of someone's mental health status, or race, or sex. It's wrong.