There are currently five countries which officially recognise three genders. These are Nepal, which since 2007 has made it illegal to discriminate against anyone on any gender grounds, and Bangladesh, which officially recognised a third gender in 2013. Germany in the same year made it possible to register a baby as being of indeterminate gender if this is unclear at birth, and a similar law now exists in Australia. The latest country to recognise a third gender is India, which passed a law in April 2014. Many other countries have laws against discriminating on the grounds of gender or orientation of any kind, but a special law allowing you to register as belonging to a diferent category is still rare.
It is thought that about 1 person in 2000 is without a specific gender. Some cultures have always been aware of this but it is only recently that the law has begun to reflect it.