I'm mad- A.K.A. never assume!

Ok why is it if you don't have your baby dressed up in pink, or in frilly clothes, or have a headband on her- people assume your baby is a boy?! I've been going through this for 10 months now- She looks nothing like a boy first of all, and if I want to dress her in jeans and a t-shirt, you shouldn't assume she's a boy! I don't want to dress her in pink all the time. Do I have to put a sign around her neck saying "I am NOT a boy"? If you're not sure, don't assume. Don't say "he" or "him" just say "the baby". Saves you the embarassment and saves me the aggrevation.

Update: It happened to me again the next day twice! I had her dressed in a lilac t-shirt, jeans and a lilac hat with flowers on it, and still she got called a boy! I have since bought a bib that says "I am not a boy" on it.