The existence of a "morning after" pill drives them up the wall.
I'm still trying to understand the passion these people have about protecting the fetus, given how little they care about the child once it is born. For example, they don't provide prenatal or post birth medical care (0-18 years), they cut education funds to the bare bones, they support "just because" wars (ones which don't directly affect the safety of the country), they make it nearly impossible for willing married gay or lesbian couples to adopt children, they don't care that the existing foster care system results in placements which in some cases make "Annie" look like a trip to summer camp, and they deny both climate change and the efficacy of vaccinations. Despite all of this, they wave the banner of being "pro-life."
Also, there is absolutely no discussion of the responsibilities of the father of the child who results from intercourse. I think any law that attempts to restrict abortion should be required to include a section on making the father totally financially responsible for the child he's sired. If the father is under 18, then the burden is placed on his parents.
Personally, I think anti-abortionists just love the emotional high they get when they argue they are protecting "the life of the unborn child." Basically, it's an addiction to adrenaline. They're all a bunch of drug addicts.