I was helping my 16-year-old daughter do her laundry the other night–in a hurry, as she was packing for a spring break house-buildng trip to South Carolina–when I noticed a small piece of red fabric caught in the bottom of the washing machine. Shoot, I thought; one of her t-shirts or pajama pants must have ripped. When I yanked it out, however, I was shocked to see that it was actually a tiny, lacy red thong–which I had never seen before and which seemed to me to have no purpose beyond arousing a sexual partner. I mean, if you just wanted to avoid a panty line, why make it red and lacy?

Now, I am quite confident that my daughter is not sexually active; we have a close and unusually communicative relationship. So when I asked her–with feigned nonchalance–about the offending panties, she explained matter-of-factly that she wanted a thong to wear under leggings, but when she searched through the 7 for $25 sale pile (that’s my girl!) at American Eagle, they didn’t have any gray cotton ones. Makes perfect sense. Still, the whole episode made me aware of how much I don’t know about her world. When did she buy it, and who was she with? And why is American Eagle–a store aimed at teens and pre-teens–selling stuff like that anyway?

When your children are babies, you know every single thing they do: burp, sneeze, poop, roll over. As they grow up, they gradually begin to do more things in private: pick their noses, get undressed, use the bathroom. By the time they are teenagers, they are living a significant portion of their lives out of your sight. Maybe they write in journals, masturbate, tell their friends things that they used to tell you. And come home from shopping trips with sexy lingerie that they don’t need yet but will soon enough. Good thing her father doesn’t know how to do the laundry.