The Dominican Republic recognises three sexual categories in its citizens: male, female, and pseudohermaphrodite. This is the result of a genetic disorder that has persisted through generations because of the isolation of the villagers of Salinas, a village in the south west of the country.

Guevedoces – meaning ‘penis at 12’ – or machihembras – meaning ‘first a woman, then a man’ – is the name of the people who get the rare disorder: when they’re born they look like girls with no testes and what appears to be a vagina. Only near puberty do they the grow a penis and descend testicles.

This occurs because of a missing enzyme which prevents the production of a specific form of the 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, male babies who carry the Y chromosome start to produce dihydro-testosterone in large amounts, which turns the tubercle into a penis. For females, the tubercle becomes a clitoris.

But some male babies are missing the enzyme 5-α-reductase which triggers the hormone surge, so they appear to be born female with no testes and what appears to be a vagina. It is not until puberty, when another huge surge of testosterone is produced, that the male reproductive organs emerge. What should have happened in the womb happens around 12 years later. Their voices deepen and they finally grow a penis.

There are around 90 guevedoces in Salinas and, although they resemble males, there are subtle differences, such as decreased amounts of facial hair and prostate glands.

And there you thought only the X-Men had mutants.

[source: telegraph]