Karen B., a Los Angeles writer in her 40s, found a sperm donor on Craigslist when decided to have a baby that she would later raise with her lesbian partner.
"I tried every male friend, gay, straight, married and single, but it was really difficult to find somebody," said Karen. "I was running out of options and my biological clock was ticking."
After connecting on the Internet, she and the donor, Daniel C., signed a layman's agreement that the child would live with Karen and she would make all parenting decisions. He would have some visitation rights.
"I always wanted the baby to know the father," said Karen, who had originally intended to use a family friend's sperm until she discovered he was HIV positive.
But as the pregnancy progressed, Daniel interjected himself into the couple's life, telling the doctor he was Karen's husband, even though he was gay.
After the birth, Daniel insisted Karen get a passport for the boy, so he could visit his native Brazil. When she refused, Daniel sued her for joint legal and physical custody.
There are no exact numbers, but using a known, rather than an anonymous sperm donor is becoming more common, especially in the gay community. Parenting agreements between mother and sperm donor, like the ones Karen and Daniel signed, can readily be found online.
But these casual arrangements, which are co-brokered at gay mixers and online, can throw new families into turmoil when relationships go sour or a sperm donor changes his mind.
The case also raises questions not only about whether sperm donors have parental rights, but what is best for the child now that reproductive technologies are creating new kinds of families.
The courts eventually ruled in favor of Karen, allowing the sperm donor to visit twice a month, but Daniel's involvement in her son's life has continued to be problematic.
In July, the Superior Court in Santa Monica, Calif. rejected Daniel's claim under the California's Sperm Donor Statute, even though his name was on the birth certificate.
"The decision in this case upholds the law, which was put into effect to protect both sperm donors and recipients -- whether they are married, unmarried, gay or straight," said Karen's lawyer, Ilene Trabolsi. "The law affords a statutory vehicle so that men are free to donate their sperm without fear of liability for child support and women can obtain semen for artificial insemination without the fear that the donor may claim paternity."
Karen ended up spending $60,000 in legal fees to fight the case, and she often wonders if Daniel will take her son, who is now 3, to Brazil during twice monthly visitations.
"A lot of my friends are concerned he's a flight risk," she Karen. "It makes me nervous. I let him see my son for four hours, but if he's 10 minutes late I panic."
Karen came forward to tell her story to help others.
"Women should use caution," she said. "I know a lot of gay and straight friends who are contemplating using a friend and I think they are unaware of the potential dangers of doing this."