Using in vitro fertilization (IVF) and pre-implantation genetic testing (PGT), prospective parents can choose which embryo they want before a pregnancy begins based on that embryo’s polygenic risk score (PRS), its chances of developing certain diseases. IVF and embryo screening have been used for years, but advances in whole genome analysis are allowing scientists to target diseases influenced by many mutations, not just Mendelian disorders linked to single genes. Eventually this capability could extend to selecting for traits like height, intelligence and strength.

Considered on its own, that’s an impressive development. But when we evaluate this technology alongside the ethical baggage it carries, all sorts of awkward questions materialize. Here’s perhaps the most important one: If parents can reduce their risk of bringing disease-prone children into the world, should they be forced to do so?

Citing the existing vaccine controversy, some commentators say “yes.” Preventing sickness and death is the ethical thing to do, they argue: it’s a “moral obligation to create children with the best chance of the best life.” Furthermore, we all cover each other’s health care costs, either through private insurance plans or federal programs. As a result, there’s no reason these treatments should be voluntary. Sex should be for fun and bonding, IVF and PGT for making babies.