Abort the rapist. Keep the baby.
By the way, in general, incest is rape. At least in the argument abortion proponents are making. Otherwise they would be talking about two "consenting adults" committing incest and having an unwanted pregnancy. In this case, again, abort the criminal not the child.
Who to punish? Start with those performing the abortions. I think the mothers seeking abortions should be counseled, just as someone attempting suicide would not be charged with attempted murder.
If i was 12-14 year old girl and I was raped I would want the choice. I would probably have the baby and put him/her up for adoption. Now if i were an athlete girl like very good at it or a model, I would think twice before giving birth.