Over the past seven years, human semen imports from the U.S. to Brazil have surged as more rich single women and lesbian couples select donors whose online profiles suggest they will yield light-complexioned and preferably blue-eyed children.

Brazil is one of the fastest-growing markets for imported semen in recent years, said Michelle Ottey, laboratory director of Virginia-based Fairfax Cryobank, a large distributor and the biggest exporter to Brazil. More than 500 tubes of foreign semen frozen in liquid nitrogen arrived at Brazilian airports last year, officials and sperm-bank directors said, up from 16 in 2011. Complete data from Anvisa, Brazil's health-care regulator, isn't yet available for 2017.

U.S. sperm-bank directors said preferences like those of Brazilian purchasers hold across their global market. "The vast majority of what we have and what we sell are the Caucasian blond-haired, blue-eyed donors," said Fredrik Andreasson, CFO of Seattle Sperm Bank, which provides about a quarter of Brazil's imports.