Besides which, hormones matter a whole lot more for human sexual differentiation than chromosomes. Birds are different, and a lot more like the naive idea of “chromosomes > sex characteristics” (which is why you sometimes get bilaterally gynandromorphic birds when a pair of zygotes—one male, one female—fuse in the egg).
Besides which, hormones matter a whole lot more for human sexual differentiation than chromosomes. Birds are different, and a lot more like the naive idea of “chromosomes > sex characteristics” (which is why you sometimes get bilaterally gynandromorphic birds when a pair of zygotes—one male, one female—fuse in the egg).