This time it was my fault. I dressed her in a white onesie, no headband, and carried her in the neutral brown car seat.
The first time today was in the waiting room of the pediatric section of the hospital. I hadn't taken the time to put Baby in anything cute because she was just going to see the doctor naked anyway. What's the point? A teenage girl nearby started smiling and waving at us, then told us we had a cute little boy. I said girl, and she apologized and said it was hard to tell. That's ok. It is hard to tell if I don't make it obvious.
The next part was on our way out of the hospital. An elderly lady asked me how old she was, then said she was a nice looking boy. I corrected her and said girl. The lady then told me that I should use Scotch tape to put a bow in her hair so people don't get confused. I looked at her with a funny look, and she said really, that's what she used to do with her daughter. I do believe this was before headbands were invented. But I was polite. I just nodded and smiled, then went on my way.
(I do have a friend who put personal lubricant on bows to stick them on her daughter's heads (they didn't have hair), but that's a different story altogether.)