Marsgender is a gender which feels similar to, and yet still not quite the same as one or both of the binary genders. It is reminiscent of how Mars is similar to Earth in terms of atmosphere, mass, etc, but still not the exact same.
History and Flag
Marsgender was coined on September 7, 2015 by Pride-Flags on DevianArt. The flag was created at the same time. The colours are meant to visually represent that of Mars.