American maths professor turned sperm donor, Ari Nagel has risen to fame for spreading his seed across America, helping women to conceive.
He's been dubbed 'The Sperminator' and has fathered 29 children with 24 women so far.
His oldest child is 14-years-old and his youngest offspring are still in the womb.
The professor has made headlines in the past for donating sperm in public bathrooms.
He's helped women conceive in a variety of ways, including trips to fertility clinics, sending sperm in the mail, DIY artificial insemination and "the old-fashioned way".
The 42-year-old has helped older women, straight couples and lesbian couples to conceive.
He explains that many women are grateful to him, and that some want him to play an active role in their families.
Nagel offers his sperm for free and says he gets a lot of joy from helping people who have struggled to have children.
He says he will help whoever asks for a sample of his sperm, whether it's in a cup or by way of "a little action".
Some of the moms had more than one kid.— Ari Nagel, sperm donor dubbed '
I have three women that are currently pregnant by me right now and all three of them got pregnant on the first try.— Ari Nagel, sperm donor
I've never charged any of the women. There's no financial gain whatsoever. I mean, kids cost money.— Ari Nagel, sperm donor
Maybe one day when these kids grow up they'll take care of me when I'm old.— Ari Nagel, sperm donor
Sometimes they want to get to know me and go for dinner first, and other times they're just ready for the baby.— Ari Nagel, sperm donor
I have children in 10 different US States.— Ari Nagel, sperm donor
I enjoy doing it in a cup too sometimes, either way it's a win-win honestly.— Ari Nagel, sperm donor
Other women are trying and their not getting pregnant. It depends on the timing, the ovulation, the age and health of the woman.— Ari Nagel, sperm donor
I can't be a full-time dad for 29 kids.It just doesn't work. Whatever role I play, I think my kids will know that I love them and I will be a positive role in their life.— Ari Nagel, sperm donor
Some of my children I've never met.— Ari Nagel, sperm donor
He spoke about his relationship with his kids, the expectations of his role, and more.
Listen to the interview during The Fringe feature on Late Nights with Sara-Jayne King: