From Girls to Boys to Older Men: The Interesting Tale of the Guevedoces and 5-Alpha Reductase Inhibitors

The study of the guevedoces, children in the Dominican Republic who appeared female at birth but developed male characteristics at puberty, led to the discovery of 5α-reductase type 2 deficiency. This condition was characterized by genital ambiguity and changes during puberty such as increased muscle mass and deepening voice. The research by Julianne Imperato-McGinley and others in the 1970s highlighted the role of dihydrotestosterone in these changes. This understanding paved the way for the development of 5-alpha reductase inhibitors (5 ARIs), such as finasteride and dutasteride, which became widely prescribed for urologic conditions. The study exemplified the progression from observing a natural phenomenon to creating significant medical treatments.