People who has 46XY usually are born with undeveloped or ambiguous external genitals. XY is male. If a penis doe snot develop, it looks like a vagina. Both structures are homologous: they develop from the same basic substrates in the organism. That is why a person with 46XY can have internal testis, male hormones, male chromosomes and a male physique, but with genitals that looks like a women's from the outside. Caster is 46 XY dsd. Biologically women do not have Y chromsones, only men. But because Caster looked like a girl from the outside when born (due to 46XY) she was legally registered and raised as a women, so even though her sex is more male, her gender identity is female.