Mr Rooney, whose eight children were born to four different mothers, travels over 300 kilometres to meet women clients and says he charges only for his expenses.
His website says the service is on offer to lesbian couples, single women, bisexual women and heterosexual couples who cannot conceive themselves. He advertises on Facebook and through a mobile phone app.
He claims his service has proved so popular that he even helped three women to conceive in a single 24-hour period.
"I've been inundated from the start," said the former web designer. "There were women who had been trying to have a baby for three or four years so it was very busy to begin with.
"I have helped people who have been to clinics where it's failed, and it has worked first time with me. There are more babies born in the UK by private donation than through private clinics."
Official guidelines for sperm donation state that legitimate donors should help create a maximum of ten families.
Mr Rooney claims to carry out health screening of all potential mothers as well as asking for proof of their income and benefits to ensure they can afford to look after a child.
He has claimed on his website that he is willing to help women either through artificial insemination or "naturally with no strings attached".
But he denies any suggestion that he has slept with women he is supposedly helping.
He told the Sunday Mirror: "I could have gone to bed with quite a few of my successes, but it's not about that. It's about helping other people."
His partner, with whom he has a three-year-old son, a two-year-old daughter and another daughter aged one, is supportive of his sperm donation service.
Experts have also raised fears that his children could grow up in the same area, raising the possibility that half-brothers and sisters might have children together.
Mr Rooney said he had ensured the women were aware of other recipients, while also claiming that their "privacy is still respected".
He has previously claimed that he does not tell clients about his past offending - he was convicted of criminal damage in 1993.
He appeared in the Daily Mail that year smiling as he left court after he admitted causing over $135,000 worth of damage with his graffiti spraypaint gang.
After serving seven months in a young offenders institution while waiting to stand trial, he was given a suspended sentence.
After the hearing he told reporters: "My barrister's a genius. I'm laughing. It's a soft touch."
The court was told police had described him as the country's most prolific graffiti artist.
- Daily Mail
