Canada’s decision, Jaworski says, is probably due to some outdated ethical concerns. Sperm donation is what economists call a “repugnant market”: an area where there are both willing buyers and sellers, but a watchful third party is opposed to the transaction for some reason. It falls into the same category as sex work.

There are a few widely-cited arguments for why sperm donation is a repugnant market. First, there’s the idea that if you pay people for any kind of donation (or other acts of kindness), you change the kind of people who are willing to donate. “Economists call it ‘crowding out,’” Jaworski says. “If you introduce an incentive, there are cases where the incentive will crowd out the altruistic impulse.” In other words, people who wanted to donate any sort of tissue from the goodness of their hearts may not want to do it if that act-of-kindness part is taken out of the equation.