A rare genetic anomaly discovered by American endocrinologist Julian Imperato in small community in the Dominican Republic saw young children changing from girls to boys when entering puberty! The children were born with female genitalia, but once they reached puberty they would form a male penis. These children are known as ‘Guevedoce’, a word meaning ‘penis twelve’, or ‘machihembras’ meaning ‘first a woman then a man’. The children during puberty display a burst of testosterone resulting in the formation of male sex organs. Imperato’s research showed that the problem was caused due to a deficiency of a particular enzyme that converted testosterone to dihydrotestosterone (DHT).