I would agree if this were a little brother or a step daughter that you "inherited" from a new boyfriend...but in this case, it's her own flesh and blood. That type of bond is really hard to become resentful over, for any reason.
Maine, you don't think there are people out there who resent their biological children? Surely you've heard of men who want nothing to do with children that they've fathered. And obviously abortion is still a common occurrence in this country.
I think maybe the reproductive freedom of the posters on this site is skewing their perspective a bit. When you are a (more mature) person who wants a child and has to work towards that end, you are going to view the situation differently than someone in their early 20s who feels like an unwanted pregnancy has ruined their life.