In a village in Dominican Republic, around 1 in 50 children are born with a rare condition where they appear female at birth and are raised as girls, but then develop male genitalia when they hit puberty. They are known as "Guevedoces" which roughly translates to "penis at 12".
Children with the condition are genetically male, meaning they have one X and one Y chromosome. However, as they develop in the womb, a genetic mutation prevents their bodies from converting the male hormone testosterone into a hormone called dihydrotestosterone, or DHT.
Because DHT is responsible for the development of male sex organs, the lack of DHT means the male organs don't develop properly, according to the National Institutes of Health.
Source: livescience.com
