Abortion is not infanticide. Under the circumstances that you describe, in which a woman is raped and becomes pregnant but is not sure if it was the rapist or her husband who impregnated her, the logical thing to do would be to get an abortion. After all, she can continue to have sex with her husband and will probably become pregnant again, but this time without the ambiguity about who the father is.

I understand that if you believe that abortion is murder, then it would be wrong under all circumstances. However abortion is not murder, and it is not wrong in all circumstances, and as I have explained, it is more justifiable in some circumstances than in others. Some people use abortion as a substitute for other forms of birth control that they could have used, and that is wrong. If nothing else, it creates an unnecessary use of scarce medical resources. But under some circumstances, the woman is not to blame for her pregnancy.

The idea that any man should be free to impregnate any woman he wants to, simply by raping her, and that the woman would then be obligated to bear this man's child, is morally repugnant. The fetus is not a person, it is only a potential person. The unfertilized ovum of a woman is also a potential person, since it can potentially be fertilized. So if we are going to treat potential persons as if they are actual persons, then it should also be illegal for a fertile woman to refrain from getting pregnant as often as she biologically can (which would be about once a year). If a woman has the capacity to become the mother of 30 children, then those 30 children must be born. Otherwise they have been murdered, right? We can't have that. Don't worry about food shortages. Science is doing amazing things with edible algae.