Men offering "natural insemination" services to women who want children

The internet has created a lot of connections but a new trend may rank as one of the most bizarre. More and more men are going online, offering to have sex for free with women who want to get pregnant.

No more paying a sperm bank thousands of dollars to get artificially inseminated. Now some women are connecting with and sleeping with sperm donors for what they call natural insemination.

One man, who claims he's fathered 30 children so far, has written a book about it called "Get Pregnant for Free on the Internet with a Private Sperm Donor." The man who calls himself "Joe" says he's married with three children of his own and that his wife doesn't know he's connecting with women online and traveling around the country to sleep with women who want to become pregnant.

"I have a Clark Kent life and then a superman life," Joe told ABC News.

Joe says he sometimes ships his sperm to buyers, but most often he sleeps with the women because they believe the "natural way" increases their chances of getting pregnant. In the past seven years, Joe claims he has slept with more than 100 women for natural insemination.

Kyle Gordy is also a natural sperm donor who says he recently had his first child with an anonymous woman. He doesn't get paid to do it and insists his motive is to have the satisfaction of knowing he's got another descendant out there. He's pursuing his master's in accounting and says women want his sperm because he's healthy, good looking and comes from a family of scientists.

Gordy posts photos of himself online, and information for prospective mothers like his hair color and IQ. And he'll answer any question they have, such as, "is your sperm good?", or "have you had success in the past?"

One of those who's slept with Gordy is 44-year-old Serena. She drove two hours to be naturally inseminated by Gordy at his home. She's never been married but the insurance broker desperately wants a child.

"I don't care if I have a husband. I just want a child," Serena said.

Sperm from a sperm bank would have cost her at least $700. Gordy was free. She'll soon find out whether it worked and she plans on staying friends with Gordy.

But during the process, she had to keep reminding herself that he was a donor, not a date. Now she's waiting for a date from the stork and figuring out what to say when her child is old enough to ask, "Who's my daddy?"

Watch the full story on ABC News' "20/20" Tonight at 10pm ET/9pm CT.