you have good morals i suppose but i just personally think that no one innocent person should ever be forced to do something they do not have to do whether another life depends on it or not. for example, if i open my doors to someone homeless for a day, that does not mean i am obligated to let them stay even if kicking them out would inadvertently cause their death. needing it to live does not make it THEIR house, the fact that houses are meant to house people still does not make it THEIR house
There really is no analogy that can be used to compare the process of human reproduction, it’s a unique experience unlike any other.
Even so, given your comparison of killing a prenatal child to that of killing a homeless person by making a choice, I must point out that both are immoral acts. Just because something is legal does not make it the right choice.
Morality must always trump legality. Remember, the Holocaust was legal. So was American slavery. Both resulted in enormous human suffering.