if someone were to get SA'd by a 'friend' or even family member- they should not have to give birth to that baby and be reminded every day of the horrible thing that happened to them. it also occurs in family very often- and giving birth to a baby that was conceived unwillingly by a family member is incest and the baby would have many issues.
as well as if the mother struggles with mental health issue she may not even be able to properly care for a baby or maybe she is too young to give it a proper good life.