4. Sex in Our Minds

Indians, almost 2,000 years ago, already attributed impotence-curing properties to the ingestion of testicles. In the Middle Ages the simple observation of eunuchs reflected the obvious fact that the testicles had a role in sexual desire and male characteristics. In the mid-nineteenth century, the German Adolph Berthold transplanted testicles between animals until suggesting that some substance was contributing to male development, and at the end of the same century, the Frenchman Charles-Édouard Brown Séquard injected himself an extract made of animal testicles and documented how they brought back his sexual desire. In the 1930s testosterone was identified as the primary androgen, leading to all the current research into its influences on embryonic development, its role in sexual dysfunctions, its decrease during andropause, its role in female sexual desire and how the birth control pill interferes with its production.