Sex is something scientifically distinct for most people. It’s defined by a certain package of genes and hormones as well as more obvious physical features, including a person’s genitals and gonads (although a small proportion of people are biologically intersex). Gender, meanwhile, is a social identity, influenced not only by biology but also by external factors such as upbringing, culture, and the effect of stereotypes.”― Angela Saini, Inferior: How Science Got Women Wrong—and the New Research That's Rewriting the Story