Actually many native American tribes differentiated between biological sex and gender role/gender identity.* There were two biological sexes: male and female. Gender, however was different. A 'Two-Spirit' person was biologically male BUT had a female, non man, non-masculine feminine gender role within the tribe. Reproduction was at the heart of Native American ideas regarding biological sex. A biological male could never bear a child, and a biological female could never impregnate a woman. Therefore their biological sex was forever immutable. A Berdache was never thought of as a being a woman or female because only women who could give birth where accorded that status.** However, the Bate, Winkte, Mixu'ga, and Heemaneh...were allowed to dress and act as women. Female pronouns were used with regard to them and they were allowed to work and socialise fully with the women of the tribe.
Our society understands the two biological sexes idea well enough. However, many people consider biological sex and gender to be the same thing. Therefore if you are biologically male then you gender identity is also male. That is why transsexuals are forced to take HRT and undergo expensive and extensive surgeries. Our society simply cannot comprehend that a person can be biologically male and chose to be socially female, or biologically female and socially male. There would be no need for pills and surgery if we could adopt the Native American idea on sex and gender.
* Gender Identity: The inner psychological feeling that one is masculine or feminine.
Gender Role: The public expression of gender identity. E.g dressing as a woman, the copying of female mannerisms & body language, imitating the female voice pitch and intonations, maintaining the cultural practices expected of women, strong preference for women's company and women's activities.
I am biologically male and socially (within the family) female. The pronouns appropriate to me are she and her and my title is Miss. I am my mother's daughter and my sister's sister.
** Some tribes reclassified infertile women into a different social gender. That is they were biologically female but socially something else. However, most of the tribes regarded infertile women as women.