TLDR. In 64811 newborns, 64674 (99.79%) were either XY or XX in accordance with observed sex. Of the 137 with chromosome anomalies, 130 (94.89%) were sex-typical. Thus, 99.99% of people have sex chromosomes entirely in accordance with their external genitalia. End/

— Dr FondOfBeetles (@FondOfBeetles) March 28, 2019