Martian (Memoirs of a Spacewoman)

Martians are a sapient hermaphrodite species from the planet Mars.

Biology
Martians are gregarious creatures which evolved in a subterranean environment and stand about 4 feet in height (~ 1.2 m). Their bodies are protected by a thick spongy shell which can shield them from hard impacts. They communicate with each other by touch using their fingers, toes, tongues and sexual organs. While they are capable of speaking, they rarely do so, as they prefer tactile communication.

Being hermaphroditic, Martians can temporarily become fully female or fully male, but will always revert to their natural state of being two-sexed. These temporary transformations can be voluntary or involuntary, the latter sometimes triggered by stress. Since their sexual organs double as tactile communication organs, their external appearance remains largely unchanged regardless of their current sex.

It is possible for a Martian, when in their male form, to impregnate a female Human. However, since no genetic material is passed from one to the other, this act results in a strange form of pregnancy in which the Human gives birth to a haploid daughter, genetically identical to the mother, but much smaller than her due to having only half the amount of chromosomes.

Culture and society
Although Humans and Martians tend to find each other repulsive, the two species have aided each other in interstellar and intergalactic exploration.

Appearances

 * Memoirs of a Spacewoman, by Naomi Mitchison (1962)