There's also incest. The reason why incest is forbidden in our society is that the children of incest often come out with severe congenital deformities. So most people agree that abortion is acceptable in those cases. But if you take that logic one step further you start euthanizing babies with fetal alcohol syndrome. When you start deciding who should live and who should die, where does it stop? Where do you draw the line? 

 Conception by incest is irrelevant to the fact that abortion murders an innocent child. If we applied capital punishment to rape and incest, perhaps there would be fewer murders of innocent babies. 

 That is what the law is for-to draw those lines. 

 Do you think incest between consenting adults and without pregnancy is ethical?