But you're a girl!

Last night, after I'd come home from grocery shopping, the Joshman was being nice and putting it all away for me. As he got to the bag with my shampoo and conditioner, he picked the bottles up and the following exchange happened:

Josh: Hmmph, sometimes I forget you're a girl and need all this stuff for your hair.
eris: I have long hair!
Josh: You're a girl!
eris: When you had long hair, you used separate shampoo and conditioner.
Josh: Yeah, cuz I had long hair.
eris: I have long hair!
Josh: YOU'RE A GIRL.