When a TIM wants to be a "woman", who does he look to for inspiration? Females. If biology doesn't matter, why do they want the physical characteristics that result from being female? Think curvy hips, breasts, voice pitch, petite shoulders, etc? If being female alone doesn't make someone a woman, why do TIM's still look to females for their goal appearance? What is passing? Resembling a female while being male.
Why do they want all the things that are associated with the female sex either biologically (periods, pregnancy, etc) or traditionally (dresses, nail polish, lingerie, makeup, etc)? I think the answer is simple: because they even know womanhood is not an identity. Womanhood is being female. And throughout time, being female has carried definitive physical characteristics from biology as well as social differences that have endured thousands of years. Womanhood has never been an identity; it's a state of being for XX-conceived humans=FEMALES.