“Welcome to my van. Or, as my wife calls it, the wanker van,” smirks Clive, a 61-year-old retired teacher from the Midlands. There’s a reason why Clive’s vehicle has no windows in the back. In order to get the freshest possible product to his customers, he pulls up directly outside their houses, clambers into the back and, 20 minutes later, appears on their doorstep with a full syringe and a serene expression.

Gird yourselves, ladies and gents, for Four Men, 175 Babies: Britain’s Super Sperm Donors (Tuesday, 10pm, Channel 4), a film that examines the gloopy world of unregulated sperm donation. Eagle-eyed viewers will notice that women don’t figure in the title of this show – which is best watched with a sick bucket nearby – despite their rather critical role in the baby-making process. Their appearance in this cock-eyed investigation is secondary to the narcissistic creeps who zigzag the country jizzing into plastic pots in order to create their own mini master-race.

On average, Clive makes 14 donations a month and reckons to have given 500 deposits to strangers. He travels up to 80 miles to make his deliveries, which means that, were he to have fathered 500 children, the gene pool in his part of the country would be alarmingly narrow. This doesn’t bother Clive, who, lest we forget, is on a mercy mission. That he doesn’t charge for his services means, in his eyes, that he’s up there with the Messiah. “Being a sperm donor is being a Samaritan,” he says.

Another self-styled Samaritan, Mark, has thus far fathered 54 babies, and has nine more in the pipeline. Several years ago, feeling “under-used” after having his own children, he visited a series of licensed clinics but was turned down on account of his age, and so decided to go it alone. “I want to reproduce with as many women as possible and pass on the genetic characteristics that I have,” he says. And so we watch Mark, who in another life would make an excellent dictator, visit a young woman who, having already had one baby with him, now wants a second. Observing his first child, Emilie, he notes: “She’s got the wonderful blue eyes that all my babies have.” Oof.

How did we get to a place where women are accepting the seed of middle-aged strangers rather than visiting official clinics? And what does this mean for their children? Alas, this film isn’t interested in finding out. While there are brief encounters with women as they take grateful delivery of the fluids, Britain’s Super Sperm Donors is firmly about the male end of the bargain. Amazingly, despite the health dangers posed to women and their babies by these rogue traders, and the potentially tortuous issue of parental rights, what they are doing is still legal.

Theirs is an exercise in power over often-vulnerable women, and a clammy affirmation of their virility. This much is clear when Clive, whose strike rate has dipped lately, finally scores a pregnancy with a woman who had previously tried, and failed, with Mark. Clive’s first thought is to text Mark with the good news. “The magic’s still there, it’s still happening,” he beams from his wanker van. Pride pitifully restored, off he drives, a eugenics hero ready to spread his seed again.