I thought that was the end of it. The happy-sad kind of ending you make your peace with and feel grateful for. Then about a week later the phone rang, and it was a genetic counselor calling from the testing company.

She had that gentle, careful voice, the kind that tells you something’s coming before she even gets to it. She said my DNA showed a marker. Huntington’s disease. “You’re a carrier,” she said.

I’ll be honest, I didn’t even really know what that was. She walked me through it nice and slow. It’s the kind of thing that gets handed down, parent to child, fifty-fifty odds every single time. Then she said it so gently. “Your biological father’s family should really be tested.” I sat down hard on the kitchen chair. All I could think about was Kevin. My boy. If it was in me, it could be in him.

So I called Linda. I didn’t even email this time, I tracked down her number and just called. She went quiet when I told her about the marker. Real quiet. Then she said, “Uncle Ray died of Huntington’s.” I think part of me already knew, but hearing her say it still landed like a brick on my chest. I made myself ask the next thing anyway. “Did Ray have any other children?”

“One,” she said. “A daughter.” I asked her where. She said, kind of surprised herself, “Well, she actually lives in your state.” My state. What are the odds of that, I thought, and I almost laughed at it. Then I asked her name. Just to be asking, really, just making talk while my brain was running in ten directions about doctors and tests and how on earth I’d tell my son.

Linda went quiet again. Longer this time. So long I thought maybe the call had dropped. Then she said something that didn’t make any sense to me at first. “She was adopted too, you know. Same as you. She doesn’t even know it.” And then she said the name.

It was Sarah’s name. My Sarah. Kevin’s wife. The woman who called me Mom every single Christmas and hugged me in the doorway every Sunday. I think I said the name back like a question, like maybe there were two women out there with it. There weren’t. Ray’s daughter, the baby he gave up the very same way he gave up me, grew up, moved to my state, and married my son.

You’ve got to sit with that a minute, because it took me a good long while myself. Ray was my father. Ray was Sarah’s father. Which makes Sarah my sister. My half-sister. And my Kevin has been married to her for eight years. They have my granddaughter, little Emma, who’s six and has the same gap in her front teeth that Kevin had at that age.