Ed Houben, a single Dutch gentleman with a knack for getting ladies pregnant, has built his livelihood on just that. He's fathered 98 children since 2002, succeeding even in some cases where doctors have failed.
In a BBC profile, Houben said he started out going to sperm banks, but after the Netherlands banned anonymous donation, he switched over to the "traditional way" of helping women get pregnant: having sex with them. He's never looked back.
Women and couples have traveled from across Europe to solicit Houben's services, which he advertises online.
Asked whether husbands were uncomfortable with his method of sperm donation, he told the story of a family he recently helped: "They came here three times and now they have a baby. They are beyond these feelings of 'Ooh, there's a stranger sleeping with my wife.'"
Houben no longer bothers making his clients sign contracts, which probably wouldn't protect him anyway. He spends time getting to know the families, and sometimes even the kids he's fathered.
Houben also keeps a spreadsheet that he can show his progeny later in life to prevent the possibility that they might unknowingly sleep together.
"If, later on, one of my children meets someone who doesn't know who his natural father is, he can consult this list," he told the BBC.
Eventually, he'd like to retire from the sperm game and start a family of his own. But for right now, he's really enjoying his job.