I'd put it up for adoption. No reason to make the child pay the price here, but no reason to accept all the psychological baggage that would come with raising the product of a rape.
do we know, from studies or from anecdotal evidence, that the products of rape get treated worse than any other non-biologically related children such as the adopted, or step, children? I'm not sure that I've ever read that they do suffer any worse than other non-biologically related demographic.
I'm not sure that they are treated worse, but I think from the woman's perspective, it would be a little strange/bothersome that every time they look at their child, they're reminded of such contradictory feelings. On the one hand, memories of a horrible rape, and on the other hand is the attachment and love of a parent for their child. I was more worried about the emotional difficulties of the parents, the child would never have to know how he was concieved.