SÃO PAULO—With “jewel-tone eyes,” blond hair and a “smattering of light freckles,” Othello looks nothing like most Brazilians, the majority of whom are black or mixed-race. Yet the “Caucasian” American cashier, described in those terms by the Seattle Sperm Bank and known as Donor 9601, is one of the sperm providers most often requested by wealthy Brazilian women importing the DNA of young U.S. men at unprecedented rates.

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.

Everyone wants a “pretty kid” and for many parents in Brazil, where prejudice often runs deep, that means “the white biotype—light-colored eyes and skin,” said Susy Pommer, a 28-year-old data analyst from São Paulo who decided to get pregnant last year after a breast-cancer scare left her eager to raise a child right away with her partner, Priscilla.