Prenatal Testosterone Theory of Transgender (PTTT) Causation: Origins and Evidence.  Do low prenatal testosterone levels in males and do high prenatal testosterone levels in females cause being transgender? The origins of this theory in eugenics and the evidence refuting the theory.  The PTTT is rooted in eugenics theory developed in the US during the first half of the 20th Century.  With support from private foundations, eugenics developed and spread to Germany and Europe.  After World War II, East Germant eugenic endocrinologists developed the PTTT as the way to get rid of transgender people in society by adminstering drugs to pregnant mothers.  If a mother was carrying a male baby, testosterone booster shots were recommended; if a mother was carrying a female baby, testosterone blockers were advised.  The scientific evidence refutes the PTTT.