Alfred Jost (1916–1991) was a French endocrinologist, and an early researcher in the field of fetal endocrinology.
[2] His research demonstrated how hormones affect the development of male and female sex characteristics.
[3] Jost was a professor at the University of Paris, and was head of the Department of Comparative Physiology there in 1972.
During the 1950s and 1960s Jost studied the mechanism of somatic sex differentiation;[5] his research showed that male characteristics must be imposed on the fetus by the testicular hormones testosterone and AMH,[6][5] and that in the absence or inactivity of these hormones, the fetus becomes phenotypically female.
He died February 3, 1991, at age 75,[8] having retired from the Collège de France, but still active as the Secrétaire Perpétuel of the French Academy of Sciences.