A woman learned her dad isn't her biological father during a family argument. Now she's determined to be open with her own donor-conceived children.

• Hayley Darknell-King learned in her 30s that she was conceived with donor sperm.
• She's now a parent to donor-conceived twins, and open with them about their origin.

Hayley Darknell-King was in her 30s when, during a family argument, she learned her father wasn't her biological dad. "It was a huge shock," Darknell-King, a former police officer in the UK, said on the Pregnantish podcast.

While she'd always known her parents had undergone in vitro fertilization, she grew up believing her father's sperm was used in the procedure that created her.

Darknell-King said her parents kept the truth — that donor sperm, likely from a medical student, was used instead — a secret because doctors told them to. "My parents had basically never told a soul," Darknell-King said on the podcast.

Now a mom of two sperm-donor children with her wife, Darknell-King said she's taking a very different approach to the truth.

She shared her story, including what it was like to find and meet her biological dad, with Pregnantish host Andrea Syrtash to raise awareness around donor conception.

Syrtash told Insider she wanted to tell Darknell-King's story, alongside that of Sydney Sharon, another mom of donor-conceived kids who found out later in life her dad had been a sperm donor, to illustrate the range of experiences and emotions that can come with revelations around donor conception.

Sharon, who works for California Cryobank, "has wonderful, exciting chapters with her donor siblings, and that that's beautiful," Syrtash said on the show. But Darknell-King's "voice is so important in this category because we need to show the good, the bad, the ugly, the real side of all of this."

Darknell-King used Ancestry.com to find her biological dad

When Darknell-King learned she was conceived with anonymous sperm donor, she was surprised in part because she shares some features and personality traits with her dad.

"Some donor conceived people report that they felt out of place growing up with their raised family," she told Syrtash. "I genuinely never felt that."

But in 2019, five years after learning the truth and a few years after becoming a parent to twins conceived with a donor sperm and her wife's eggs, Darknell-King took an Ancestry.com test to learn more about her heritage.

The kit connected her to a distant cousin, and she used her sleuthing skills from her days in the police force to narrow down her biological father to a set of brothers. After figuring out who was who, Darknell-King wrote her dad, Jonathan, a letter.

Jonathan invited her to meet, and when she did, "it was like looking at a familiar stranger," Darknell-King said. She instantly recognized her pointy nose in his, and the duo got along naturally. They've kept in touch for the past few years — a relationship she's open with her parents about.

"It's kind of nice that it's come full circle because I was very adamant that I wanted to break that cycle of shame and secrets, and I didn't want to keep that part of my life secret from my family, either," she said. "It's opened up a lot of good communication with my parents."

Darknell-King made sure her twins can contact their biological father

Darknell-King and her wife chose a non-anonymous sperm donor who was open to being contacted by his children. "We didn't want our kids to have to use a DNA test or go searching," she said.

Darknell-King isn't genetically related to her twins, but is comforted by her first-hand knowledge that she can still share a strong bond with them.

"Being donor conceived myself, and knowing how much love I've got from my dad, and we share no genetics, and how similar we are with lots of our interests," she said. "That's nothing to do with genetics — that's all to do with how we were raised."

To hear more of Darknell-King and Sharon's stories, listen to the Pregnantish podcast.