Species with three or more sexes

This includes human species (in future or alternate incarnations), humanoid species, and non-humanoid species. Includes species with more than two genders, as well as species which are defined as hermaphroditic; does not include single-sex species in which one of the currently existing human sexes continues to exist, such as parthenogenetically-reproducing all-female species.

Future or mutated humans

• Isaac Asimov. Foundation and Earth (1986) [a hermaphroditic variety of humans; one joins the protagonists]
• Future humans in Proud Man by Katharine Burdekin.(1934; 1993) A human from the future visits 1930s England; humans in the future have evolved "beyond" humanity, and beyond humanity's bi-sexed nature; each individual can reproduce on their own, and is whole, containing both male and female attributes. This human contemplates with amazement the various social oddities of modern English society.
• The Wraeththu, future humans; by Storm Constantine
• The blands, a neuter third sex in Carolyn Ives Gilman's Halfway Human
• The future human Gethenians in Ursula K. Le Guin's The Left Hand of Darkness: Neuter most of the time, but male and female in potential; when they go into kemmer, a type of genderizing heat, they go into one or the other gender.
• The sai in Stephen Leigh's Dark Water's Embrace and Speaking Stones, a third sex that is needed by the other two (male and female) to reproduce on an inhospitable colonized planet
• Future humans in Shadow Man by Melissa Scott. (1995) space travel creates five common genders

Alien humanoids

• A hermaphroditic female-ish humanoid species in Stranded by Camarin Grae. Stranded (1991, Naiad) (3 women from a hermaphroditic species are sent as "disembodied minds" to Earth to stop a villain. They end up identifying as lesbians and fighting a fundamentalist movement led by the villain.)
• The three-way species, including human species, in Dark Water's Embrace (1998) and Speaking Stones (1999) by Stephen Leigh. Includes male, female, and "midmale".

Non-humanoids

• Chocky, an alien non-gendered species
• William Tenn's short story "The Seven Sexes," featuring an alien race in which all seven sexes must participate to mate.

Others

• Duchamp, L. Timmel. "Motherhood, Etc." (1993)
• Joyce, Graham, and Peter F. Hamilton. "Eat Reecebread" (1994)

• Oankali in Octavia Butler's Xenogenesis trilogy

See also

• Neuter and androgynous species in SF
• Species with three or more sexes
• Single-sexed species
• Hermaphroditic species in SF