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.

This episode reviews the evidence for the prenatal estrogen theory of being transgender in natal males. Since estrogen does not readily penetrate the brain, the evidence cited for the estrogen theory involves the synthetic chemical diethylstibestrol or DES. This drug was given to pregnant females during 1940's through the 1980's but was eventually banned because it caused cancer in female offspring who were exposed through their mothers in utero.  Because of this, most of the research was conducted with exposed natal females.  Research with exposed males was initiated by DES-esposed researchers who believed that they were affected to become transgender. They started a website for DES exposed males and found that 150 of the 500 males who joined the website thought that they were transgender.  This episode provides an answer as whether the evidence supports whether DES causes being transgender and the status of the estrogen theory of being transgender.

This podcast covers for transgender genetic gender behavior predisposition in the form of biomarkers and "natural experiments." Biomarkers include handedness, 2D4D finger length ratio and FTM anatomy.  Natural experiments include the saga of David Reimer and the effects of raising males with cloacl extrophy in the feminine gender behavior category.

Two new papers have been published that conclusively demonstrate the genetics of gender predisposition.  In this podcast, the Transgender Scientist will provide information on these new studies and what they mean.

Factors in transgender causation.  Why are people transgender? Dana Bevan, The Transgender Scientist identifies 4 factors. They involve genetics, epigenetics, Western culture, and early childhood learning.  This episode provides a top-level description of the 4 factors which will be detailed in subsequent episodes.