Clive, from Stretton, Derbyshire, a 62-year-old retired teacher claims to have fathered 67 children from the back of his van after donating sperm.
He contacted potential 'recipients' through sperm donor Facebook pages and waited for them to get back to him.
Clive said: "I drive somewhere where I'm not likely to be disturbed and go into the back of the van and pull the curtains down.
"Then I take the cup and a syringe so the stuff can't come out, put a bag under my arm and text them to say I'm outside and I'll be round in three minutes.
"If that doesn't work sometimes they suggest I meet them in a car park.
Clive said he only told his wife of 39 years a couple of years ago.
The Human Fertilisation and Embryology Authority said all donors and patients should be treated at a licensed UK clinic in the wake of claims by retired teacher, Clive.
A spokesman for the Human Fertilisation and Embryology Authority said the organisation was unable to stop people from making their own sperm donation arrangements.
They added: "There are risks for people who make arrangements outside the regular clinic environment.
"For example, without the proper consents in place, the donor is likely to be seen as the legal parent, with all the rights and responsibilities that involves.