which leads an observer
that you are of a particular gender
. Long hair
is, for Americans at least, a female gender cue, which is why George Wallace told so many guys to get haircuts. (Thankfully it's becoming decreasingly so.) Short hair, ties, and beards are male gender cues. Skirts and makeup are female gender cues.
Some people like to mix and match their gender cues, with the upshot of confusing observers. Though I personally lack the inclination, or maybe just the guts to do so, I applaud such people.