I'm a 54 year old woman. My brother is now my sister (and has been for about 5 years). I've had two 8 week sessions of psychotherapy to help me accept this. I tried really hard. But I can't. It boils down to this:
EVERY SINGLE WOMAN I've ever known, carries a fertility wound - its the unexpected period, covering up the blood, throwing away knickers in public toilets, fear of pregnancy, side effects of contraceptives, miscarriages, terminations, shame for feeling relieved, guilt for making "not now" or "not with him" choices, feeling ashamed & responsible, fear of judgement, the saint/slag impossible identity, yearning for babies that can't be, the failure of a baby who won't breast feed, the madness of PMT then menopause etc etc & on & on.
These are the secrets women carry & live with. This is why we need privacy in bathrooms, youth hostel dorms, gym changing rooms, and the like.
My "brister" can never know this; which makes his "womanhood" a fantasy which I cannot indulge.