Think about the collective experience of humanity before them. If you were a prostitute and got pregnant, it wasn’t about you, it was about that child’s experience as a fatherless individual, being raised by a person that can hardly provide for herself. As well as, what a child raised in that environment, is more inclined to do to other people.
Now that has changed if only because the link between sex and children, in most minds, has been broken. In those where it hasn’t… that’s the natural area where restrictions on birth control and abortion come from.