Last time I checked sex and gender were interchangeable. For ALL living organisms sex or gender is determined by the sex organs except for asexual entities such as the amoeba, bacteria or viruses that do not rely on sexual reproduction for propagation of the species. Humans rely on sexual reproduction.

Are you suggesting that when the sonogram says determines that the fetus IS female, we should hold off on that until the child grows to be an adult when he can properly express what gender it THINKS itself to be?

Certain standards are necessary, and if we throw that out the window, then confusion will ensue. Gender or Sex are BIOLOGICALLY determined variables. Ever changing social norms shape our perception of such a variable, from period to period, but ultimately shouldn't effect it.

A paralogue is race. Race is SOCIALLY not BIOLOGICALLY determined and the popular eugenics movement emphasizes what happens when we think otherwise.