After a 23andMe DNA test, Northern California woman discovers 3 siblings

Siblings Tim McNulty, Jaclyn Baxter and Loren Chase. Baxter discovered her siblings after taking a 23andMe DNA test in March 2017. Siblings Tim McNulty, Jaclyn Baxter and Loren Chase. Baxter discovered her siblings after taking a 23andMe DNA test in March 2017. Photo: Courtesy: Jaclyn Baxter Photo: Courtesy: Jaclyn Baxter Image 1 of / 4 Caption Close After a 23andMe DNA test, Northern California woman discovers 3 siblings 1 / 4 Back to Gallery

As a 33-year-old mother of two, Jaclyn Baxter took the mail-in DNA test primarily to learn about her genetic health risks. On a Sunday in March, she spit into a test tube and sent the sample to 23andMe, a genetic testing firm based in Mountain View.

When she received the online results about two months later, on Mother's Day, Baxter discovered she had healthy genes and a predominantly British ancestry. She also discovered she had a half brother.

The Placerville resident, estranged from her birth mother and having lost her father after years of illness at age 18, turned to her uncle to spill the family secrets. He knew nothing, so she decided to message her half brother directly on Facebook.

"As soon as I saw his photo on Facebook, my whole body knew it was my brother. I just knew," Baxter said.

After a brief waiting period, Baxter's brother, a Berkeley firefighter named Loren Chase, responded, and his messages only served to thicken the mystery. Chase said he was a "donor-conceived kid," and years earlier, he'd discovered a half brother of his own, named Tim McNulty.

The three took an additional DNA test. Weeks later, it was confirmed: Baxter, raised as an only child in Concord and later Pollock Pines, now had two siblings.

At the same time, Baxter's cousin — the daughter of her father's sister — took a DNA test. Baxter and her cousin found they had no DNA in common. Baxter's father, the man who raised her since birth, was not biologically related to her. Her biological father, like that of her newly found siblings, was a sperm donor. All she knew about him was from a donor registry: UC Berkeley grad student, tall, blonde, blue-eyed.

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Baxter began combing through a series of donor registries, searching for her father and any other siblings. Based on her and her brothers' birthdays, she knew her biological dad had donated sperm between at least 1979 and 1983.

"It sent me into this worry," she said. "Like Jesus, in the last eight weeks I've gained two new siblings. If it's coming at me this fast, how many more are headed my way?"

There are no federal laws limiting the number of children born from a single donor's sperm nor are there precise records denoting how many children a sperm donor has fathered. According to a Slate article titled "The Sperm-Donor Kids Are Not Really All Right," 30,000-60,000 children are born in the U.S. via artificial insemination. What accounts for the huge discrepancy? No entity is required to report on such statistics.

A Google search of "How many children can be fathered by a sperm donor" returns a series of similar headlines: "LA sperm donor connects with 19 children he fathered" (Daily Mail), "I fathered 800 children, claims sperm donor" (BBC), "One Sperm Donor, 150 Sons and Daughters" (New York Times). Such headlines, though egregious in tone, belie the challenges facing a donor-conceived child in search of her siblings.

23andMe spokesperson Eve Darmoo said stories of customers finding unknown relatives on the site are not common, though not unheard of.

"Often these are stories from adoptees, but we do have a number of customers who were donor-conceived children who have connected with siblings and even donors," she said.

Darmoo also stressed that customers must opt-in to the site's "DNA Relatives" feature and must give permission before their information is shared with other potential matches.

Baxter spent weeks wading through the quagmire of donor registries and DNA testing sites, knowing that her biological father and any number of siblings could be out there, but that the chances of her finding them were slim.

As she wrote in a post on her blog Gin and Zin, "Can you imagine finding out that you might have 10, 20, 30 siblings – or more?"

Then, while en route to Southern California, where she'd be meeting up with her half-brother Tim, Baxter received a notification from one of the DNA registries. Another half sibling had been found; this time, a sister.

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Shortly after the new sibling discovery, Baxter and her brothers met for a family reunion of sorts in Northern California – six adults and eight children brought together by a series of spit samples.

Baxter says her young kids took it all in stride.

"They're just excited to have more cousins," she said.

Since their July meeting, the siblings have continued to keep in close contact, catching up at least once a week by phone. Baxter says besides her husband, they're the first people she calls on a bad day.

"This is a happy ending for me," Baxter stressed. "Even though its been a shock and full of difficulty, at the end of the day, love is love. Now I have the siblings that I've always wanted."

Though they have found each other, many questions remain unanswered, including who their biological father could be.

Baxter says she goes back and forth between wanting to find him and letting him lie in anonymity.

"Should I be trying harder to find him?" she pondered. "What if he's the worst? What if he wants nothing to do with us?"

Despite her persistent fears, Baxter knows finding her biological father won't change the relationship she had with the man who raised her.

"It would have been an honor to be biologically his," she said. "It's still an honor to be his. If anything, this ordeal has explained why he did the things that he did."

"He wanted me so bad."

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Baxter and her newfound family are aware of an additional sibling. They don't know much about them, whether they're male or female, living or not.

When Chase's mother was pregnant, the donor agency called to tell her that another mother was pregnant with the same donor's sperm. They were calling because the mother's baby had tested positive for Down syndrome. The sperm bank wanted to ensure the donor wasn't passing down the gene.

This, says Baxter, is always in the back of her head.

"I don't know the extent of their Down syndrome, if they've been able to advocate for themselves," she said. "I would just love to give them a big old hug."

Baxter first shared her story on her blog, Gin and Zin, and later with the Sacramento Bee.

Read Michelle Robertson’s latest stories and send her news tips at mrobertson@sfchronicle.com.