Stuck in the Middle with You: Inventing "Normal" for Sex and Gender

These differences in human development, sometimes detected at birth, sometimes remaining hidden till autopsy, occur in such a vast array it's hard for medical science to generalize about them. However, while their effects on genes, bodily appearance, sexual function, and hormones vary -- they all call into question our untested truths about sex. And, by extension, any strict biological basis for gender.