Girls in an isolated Caribbean village of Salinas in the Dominican Republic become males and grow penises when they hit puberty due to a rare genetic disorder.
UK Daily Mail reports that an estimated one in 90 children born in the village make the transition by the time they reach 12.
The condition is so prevalent it is no longer considered abnormal and the children are simply referred to as the "guevedoces" - which literally translates as "penis at 12".
The children, known as pseudohermaphrodite suffer from a rare genetic disorder, caused by a missing enzyme which prevents the production of a type of male sex hormone - dihydro-testosterone - in the womb.
All babies in the womb, whether male or female, have internal glands known as gonads and a small bump between their legs called a tubercle.
At around eight weeks old, male babies who carry the Y chromosome start to produce dihydro-testosterone in large amounts - this turns the tubercle into a penis. For females, it becomes a clitoris.
But some male babies are missing the enzyme 5-α-reductase which triggers the hormone surge. This means they appear to be born female with no testes and what looks very much like a vagina.
Then when puberty hits, a large surge of testosterone triggers the male reproductive organs to grow. This causes their voices to deepen and the development of a penis.
Essentially, the development that should have taken place in the womb with these children happens around 12 years later.
