Unfortunately, these things do occur. Nevertheless, no matter how conceived, a fetus is a baby in the making. It's a human being, and we must respect human life in all phases and forms. Let's say your daughter was brutally raped. A horrible and degrading experience.
Criminal behavior is against the rules of society.
If the laws are broken in such a hideous way as to make clear that someone is depraved, they do not deserve the respect of society, and their lives can be ended. The Bible teaches that from the worst of circumstances the best may result. Unfortunately, every day, we are all reminded of things that we cannot control and that are beyond resolving. The Bible also says, Thou shalt not kill. I believe the Bible is referring to the individual in that circumstance, not to the norms of society.