Biological Sex

Biological sex refers to a set of physical characteristics, including chromosomes, hormones, gonads, and reproductive anatomy, used to classify people as male, female, or intersex. The National Institutes of Health describes it as a multidimensional biological construct rather than a single trait. These characteristics do not always line up neatly: intersex people are born with sex traits that do not fit typical male or female patterns, which is why many scientists and educators describe sex as a spectrum. Estimates of how common intersex variations are vary widely by definition, with a frequently cited figure of about 1.7 percent. Biological sex is also distinct from gender identity, which is a person's own internal sense of their gender.