boy: I bet she likes the flowers because she's a girl.
me: I think she likes the flowers because they're colorful.
boy: And girls like flowers, and she's a girl.
me: The other thing she really likes right now is trucks.
I was actually kind of impressed that he gendered her correctly, given that she was dressed entirely in navy blue. I think it's the hair clip. As far as I can tell, kids are still looking mostly at her hair for gender cues, while adults rely more on clothing.