The likely hood that this child will grow and thrive in a happy home greatly diminishes. The mother will try to raise the child till she a) breaks down, b) becomes regretful of, or c) worst of all abuses the child either mentally or physically because of the constant reminder of her attacker. All three of these scenarios will probably land the child in the nations bloated underfunded public foster care system. The child will bounce around from home to home to home until he/she is old enough to live on his or her own and by that point will either rise above which is not likely or will enter into our prison system. MOST scenarios lead to a not so happy life for the child. That's a whole lot of "what-ifs" and worst-case scenarios you got there. Your solution is to "help" the youngster out by chopping it up, or pouring acid on it until dead?
How about instead pursuing the adoption route? Or work to help people caught in difficult circumstances caused by violent, heinous crime? Recategorizing some humans to non-human status to justify abuse and murder is a practice of the evil throughout history, not of the good.