Or just the simple logical realization that the preborn child is either life or not life, and you can't kill the child simply because of the crime committed against the mother. If you can argue that trauma suffered by the mother justifies taking the innocent life that had nothing to do with it, then you're one step away from justifying the same thing for other hardships incurred by the mother.
For sure. There are basically two main thought processes in the secular pro-life movement from what I have seen.
The first states that abortion is murder, and this cannot be allowed under any circuмstances due to the child having a right to life. Typically these people allow for medical exemption in the case of a life threatening condition for the mother, but they often do not wish to include rape or (the even more dubious) incest exemptions.
The second says that unborn children are alive and do have a right to life, but they base their allowance for exemptions on the personal responsibility of the parents. If a women willingly did the action that she knew could lead to a baby (however small the likelihood due to birth control) she is responsible for taking care of it and should not be allowed an abortion. This is good and all, but is less logically consistent as people from this group generally wish for rape exemptions since the mother wasn't responsible for the existence of the child. I guess if your father is a rapist, your mother gets to decide if you're human or not
It does make you wonder. What if the father shows himself to be a rapist after children have already been added to the mix? Is this
where the idea of post-birth abortion comes from?