It’s a boy. It’s a girl. Or, is it genetic engineering run amok?

Researchers at Houston’s Baylor College of Medicine will allow 200 couples undergoing in vitro fertilization to choose their babies’ gender.

The study has already received inquiries from 50 couples, according to the Guardian. Only couples who already have a child of one sex, and want another of the opposite, are being considered. Participants will have to answer detailed questions about why they want to have a boy or a girl. The study will follow the families after the children are born and as they grow up.

So-called social sex selection is frowned on by the U.S.’s major medical associations, and it’s outright banned in several countries, including Britain and Canada. The researchers at Baylor spent nine years winning approval to conduct their study because the practice is so controversial. Their goal: to understand why parents want to choose a baby’s gender, and what impact that choice will have on their families.

Critics fear that this takes family planning too far, leading toward a designer-baby future where a child’s hair and eye color, athletic ability and who knows what else are preselected by Mom and Dad before birth. But never mind the dystopic futuristic scenarios. There’s also the discrimination argument, right now: “If you believe in equality as enshrined in international human rights, it’s illogical to allow social sex selection,” Dr. Francoise Shenfield, a member of the ethics committee of the European Society for Human Reproduction and Embryology, told the Guardian. “It necessarily means that one sex is preferable to the other for that couple.”

One of the researchers conducting the Baylor study says that many of the ethical arguments against sex selection don’t apply when it’s used by families, like the ones in their study, who are interested in family balancing. So, if you already have one boy and want a girl, or already have one girl and want a boy, is that discriminatory or just inclusive?