Also, people who claim that it's really hard to tell someone's sex without making them drop their drawers tend to operate on the mistaken assumption that sight and hearing are the only two senses that are involved in sussing out someone else's sex.

In fact, over many thousands of generations, we humans have evolved to be be highly attuned to and aware of our environment and other creatures in it - and female humans in particular have evolved to have a very sharp-honed ability to discern almost instantly other people's sex by quickly processing sensory input/data of all sorts, much of which is beyond or below our conscious awareness.

Obviously, smell is big factor, but a lot of the olfactory input we pick up on isn't something we can pin down definitely as a noticeable smell - it's pheromones that we don't detect consciously and would have a hard time putting into words.

And not to sound too woo woo and "out there," but humans - especially female ones - have evolved to very quickly pick up on the vibes, energy, electricity, emotional state, level of tension, creepiness (or lack thereof) and other intangible qualities that emanate from the people we encounter IRL. There's good reason we speak of having "gut reactions" and we say that some people and situations automatically make the hair on the backs of our necks stand up, give us goosebumps, or cause us to feel apprehensive, uneasy and on guard.

Finally, even if we focus only on what we can see, there are so many visual cues that tip us off to another person's sex other than the ones that TRAs think are the only ones that matter. Such as the size and shape of the hands and feet; the turn of the ankles, wrists and forearms; the shape of the hips, thighs, shoulders; the obvious, artificial look made by implanted sacs of gel or fluid in male chests; and the often totally inappropriate "super sexy" attire these guys wear in broad daylight when they in middle age or later decide to venture out in public in "girl mode" (to borrow Eddie Izzard's term).

Moreover, whereas TRAs think that everyone is fooled coz we all see just one or two features or details of of "transwomen's" appearance - such as hair/wig length; the "girly" tilt of their heads; their artificially plumped-up and colored lips; the perky fake globes bobbing on their chest; the pancake makeup and contouring - in fact we all take in and process the totality of other people's appearances and all the zillions of cues large and small emanating from how they look at the same time.