Every week on Explain It to Me, Vox’s call-in podcast, we answer the questions that matter to you most. When we got a question from a listener named Hannah, it piqued our interest. She wanted to know: How do you find a long-lost relative?

“I was raised by my mom,” she says. “I knew my dad was out there somewhere, but I never really gave too much thought about it because I did have a pretty full life.” By the time we spoke with her, she had found her father online and reached out to him. But it raised an entirely new set of questions. “I never gave much thought to, ‘Okay, so now what?’”

Journalist Libby Copeland has spent a lot of time thinking about those next steps. She’s the author of The Lost Family: How DNA Testing Is Upending Who We Are, a book that looks at the ways at-home DNA testing has shaped families. “This whole question around the distinction between biological and non-biological family and roots and identity, it’s everything to me,” Copeland told Vox. “I think it’s so intrinsically connected to existential questions around who we are and how we get to decide what to be.”

On this week’s episode, we discuss with Copeland how to find family, the way at-home DNA tests have changed things, and what to do if you come across an unexpected relative. Below is an excerpt of the conversation with Copeland, edited for length and clarity.

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Has this reporting changed the way you think about family?

Definitely. I grew up in my biological family, so I’m not someone who was donor-conceived or adopted. But spending so much time talking to people who don’t have a genetic connection to the families that they were raised in, it’s really interesting to hear just how much pull that genetic family has over you.

In my family, we were able to connect with ancestors in Sweden, and then we traveled there and we’re able to connect with a second cousin of........

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