Here is an essay written by the vice-president of the International Intersex Organisation.
Curtis E. Hinkle
Who is a woman?
Who is a woman? This is a question that some are now asking themselves. I have heard say that a woman is defined by her birth certificate, her hormones, her chromosomes and her genitals.
But all this still cannot and does not define what a woman is; because there are women with high counts of testosterone who even grow beards, others whose chromosomes say xy, xo, xxy, xxxy, xo/xy not to mention those of us who are born with ambiguous genitalia ... yes, intersex people!
I know of many a woman who expresses her masculine side without wanting nor desiring to be male identified and the same goes for men who demonstrate a rather strong penchant for their softer, more feminine side. These people still represent their gender, they are on some point of the gradient scale of their gender is all.
Masculine women and feminine men is something most of us are familiar with and accept but what of the woman who tells you she is a prisoner in her male body? What of the man who says the same thing, are they hallucinating or fantasizing, have they gone off the deep end of sanity?