Franz Josef Kallmann, MD (July 24, 1897 – May 12, 1965), a German-born American psychiatrist, was one of the pioneers in the study of the genetic basis of psychiatric disorders.

He developed the use of twin studies in the assessment of the relative roles of heredity and the environment in the pathogenesis of psychiatric disease.

[3] Paradoxically, he had been a student of Ernst Rüdin, one of the architects of racial hygiene policies in Nazi Germany.

[4] In a speech delivered in 1935, while still in Germany, he advocated the examination of relatives of schizophrenia patients with the aim to find and sterilize the "nonaffected carriers" of the supposed recessive gene responsible for the condition.

[5] In 1944, he described a congenital endocrine condition (hypogonadotropic hypogonadism with anosmia) that has come to be known as Kallmann's syndrome.