Annie, 35, wants a baby, but she doesn't have a partner. If she could afford it, she could go down the official and regulated route to a fertility clinic and get pregnant using donor sperm. But that could cost thousands of pounds. So instead, she's gone online and entered the world of unregulated sperm donation. Jolyon Jenkins investigates this shadowy world. It's illegal to sell sperm, but some men are making a living doing so. Others offer free sperm in return for "natural insemination", i.e. sex. Some women report that men who start by appearing to offer free sperm, gradually exert pressure on them to have sex. But what of those who want neither money nor sex in return for their sperm? Jolyon discovers the world of the "super donor" - men who compete to inseminate as many women as possible, in an acknowledged bid to spread their genes as widely as they can. Their activity can border on the obsessive."It is a bit like stamp collecting really," says one. "I devote three hours per day to it, through travelling to donate or arranging my spreadsheets or doing my photo albums of the children". The risks to women and their children are obvious - sexually transmitted infection, hereditary conditions unwittingly passed on, and accidental incest between half-siblings. If women could afford to use the official channels, they would be much safer. Instead, they are being driven into the hands of sexual adventurers, serial liars, and hobby eugenicists. Presenter/producer: Jolyon Jenkins.