Fun fact: Pregnant women can't have a whole lot of regular, mild medication. Like certain painkillers and shit. Can't imagine roofies being healthy for a gestating baby. Stress hormones impact pregnancy and labor too.
By drugging and raping his pregnant gf, he was harming the child in the process. pregnant chicks aint even supposed to have alcohol for risk of fetal alcohol syndrome.
if someone is discovered to have drugged and raped a pregnant woman, it's unlikely to be treated as completely irrelevant when they later want access to the kid that they were drugging too. plus, registered sex offenders aren't allowed to work in schools etc, whether or not their actions involved kids.