[agere_contra]

If a person has an X and Y chromosome, he is male.

I forget the exact fraction but about 1 in 20 woman are XY, believe it or not. Basically the Y chromosome is not the sole sex-determinant. XY women are testerone-insensitive, and are more feminine than XX women.

[agere_contra]

testerone testosterone

[Ragnorak]

I don't doubt that they teach that in college these days but, I think that one needs to backed up with a reference.