(1) (embryology) The developmental process in which the sex of a bipotential embryo is fixed or determined through the sex chromosomes contained.
(2) (diagnosis) The way by which the sex of an organism is determined. It may be based on the type of gametes or sex chromosomes present in an organism.
Sex determination in humans can be done by morphological examination or by chromosomal tests. Barr test is once commonly used test to determine the sex of an individual. Amniocentesis is also one way to diagnose the sex of the fetus in utero.
See also: sex chromosome