Male JW will be 'counseled' when their clothing style, hair, speech or manners are 'too feminine'.
Female JW will be 'counseled' when their clothing style, hair, speech or manners are 'too masculine'.
'Counseled' means to be coercively talked to until you either give in, or can be reproved for disregarding the elders' authority.
I'm not even talking cross dressing here. Just a female with very short hair who (mostly) wears pants and shirts will be viewed and treated as spiritually weak.
Or a male with soft voice and many delicate gestures (think Prince).
Anybody who deviates from the norm as portrayed in the pictures in the literature will be looked down upon.
And yes, your biological gender determines how you should act and be dressed.
I personally know of someone who was raised as a boy (external sex organs indicated as much), felt more like a woman during puberty, and (after chromosome testing) turned out to actually be a woman biologically.
Only after producing the test results she was permitted/ordered by Bethel to be a woman from now on. Oh, a corrective surgery (removing the man-like parts) was also done (possibly because Bethel 'encouraged' it).
Imagine this person would have been a guy by chromosomes, but still identified as a woman? Instant disfellowshipping! Or she would have to act like a man, and lie to herself the rest of her JW life.
And yes, it's a cult. Run.
Be religious with a different group if you must. Maybe a group that actually worships God instead of the Governing Body. But you know that already)