I don't ever describe myself as a female. I guess that should be evident too unless people have an other gender identity. Even in third person, I will refer to a man as a male colleague or a woman as a female colleague or just colleague for both and specify the gender only if prodded.

With regards to fashion, I agree that sometimes you dress up to feel good and on other days you do not want to be bothered. I read somewhere that being presentable is basic politeness. It is rude to show up anywhere anyhow. I am stressing on 'presentable' because I don't think one should have the pressure of looking like a chic model, but wear whatever they are comfortable with, something that suits the occasion.

Also, I agree that women don't necessarily dress up for the opposite gender.