I said yes to one night of babysitting and uncovered a truth hidden for eight years. Kelly, a mom since sixteen, asked me to watch her son Thomas. I agreed without hesitation, though Ryan scoffed. “Why babysit someone else’s kid for free?” he muttered. I left anyway. Thomas greeted me like sunshine. We played, ate pizza, and he fell asleep mid-laugh. Carrying him upstairs, his shirt lifted. A birthmark—a small crescent I’d kissed countless times on Ryan—stopped me cold. Looking closer, I saw Ryan’s face in his.

Shaken, I bagged Thomas’s spoon, then pulled hairs from Ryan’s brush. The week waiting for results was torture. The email came: Probability of paternity: 99.9%. I called them both over. Kelly arrived first, then Ryan. They sat side by side as I turned the laptop toward them. “It was one time in high school,” Kelly whispered, breaking. “I left town and never told him until later. I didn’t want to ruin your life.”