"I started to feel kind of overwhelmed," Gullicksen said. "After that burst of activity, I pondered what I could afford to do. I am not going to marry mommy and move into the house, though that goes away pretty quickly. I have a life."
"It causes a lot of conflict and angst in their lives and if there is a way I can help with that, I do," he said. "I am not just sperm or a big mystery. I am a regular guy and don't bring my agenda."
Over time, he was able to make the commitment to form an extended family, visiting each of his donor offspring in their own homes.
As a group, the seven half-siblings go out to California for a week once a year for a group reunion of boating and hiking in the Sierras.
But those who are not so lucky to find their sperm donors say they feel lost without knowing their genetic identity.
Emily Silver, 30, of Bend, Oregon, has been on a "spiritual" search to locate her own sperm donor and any half-siblings. Along the way, she has helped others people find their relatives.
Now in the licensing process to be a psychotherapist for such families, she has a twin brother. It's also difficult to fully engage her parents out of respect for their feelings.
"There are a lot of unknowns," she said. "I wonder why I look the way I look. The shape and color of our eyes is not from my mom's side of the family. I know this sounds superficial, but I have always had more curiosity about people, why they are the way they are and genealogy, and I don't have answers for that."
She also is married and starting to think about having a child, but has no medical information about her paternal side.
"I think if I found him it would fill in a lot a lot of the missing pieces," she said.
Silver contacted Oregon Health and Sciences Andrology, where she was conceived, and eventually four men got back to her.
For two years, she corresponded with one she thought was her donor, but when he finally unearthed his donor number, they did not match.
Silver also had a year's relationship with a woman she thought was her half-sibling, but after DNA testing, they realized they were not sisters.
"It's like opening a Pandora's box," she said. "I anticipate the worst. I feel like I am intruding on their lives. They have probably closed the door 30 years ago and they are shocked and don't want to deal with it."
Sperm donor-offspring relationships can be complicated, but some, like Chase Kimball and his daughters, have happy endings.
"I told them [I'd] be anything they wanted me to be, your father or your uncle, [to] call every year on Christmas or anything in between," he said of first meeting them in an ice cream parlor in 2006. "You have to have your boundaries."
The girls were astounded at how much their donor father looked like the older sister and they all shared a love of books.
"My elder daughter said something about she was glad I was a lawyer because she expected me to be a night manager at Burger King," he said. "They are both very smart.
"The biggest challenge is trying to figure out how to relate to my daughters as adults and not step on their toes," he said.
"They had financial struggles when they were younger and I know that was hard on them," he said. "It's really bothered me to know that I would have helped. But I didn't know them then."
Today, they are close and speak frequently.
"I am absolutely thrilled out of my skull with my daughters," he said.