Writing for a species with more than two genders.

Specifically, four. I'm finding that it's hard to think of how this is all supposed to work. In fact, it's hard enough that I'm just sweeping the matter under the rug until I figure it out.

This is for a loosely humanoid species evolved from serpentine flying creatures. Really, if any of you have ideas, I'm willing to consider anything.

Three of the sexes have to mate with the fourth to produce a viable embryo that the fourth sex carries.

or

Sex A has to mate with Sex B and Sex C (not necessarily the same member of sex A in both cases) then Sex B and C both mate with Sex D to deposit semi-fertilised somethings into Sex D which then combine and are carried by Sex D. Perhaps some of Sex D's genetics get introduced while the things from B and C are combining or perhaps its only input is the unique prions etc that shape the development of the fetus during gestation.

The offspring in that later case could carry the genes of up to five parents (with different Sex A partners for sexes B and C)

Perhaps one of the sexes doesn't participate directly in the reproductive process at all? They could be sexless soldiers or laborers or something. Or maybe they are the ones responsible for actually caring for the offspring, so while the other sexes provide genetic information, the fourth provides behavioral.

Another idea: They serve as a 'swiss army sex'. They are born asexual, but if circumstances arise where one of the other three sexes become scarce they can develop the characteristics of any of the other three to compensate. Sort of like what clownfish or frogs do, except they start as kind of a blank slate.

What exactly is your problem, anyway?

Perhaps successful mating still occurs between a pair of such creatures, but it can be a pair chosen from any pair of the sexes; the choice of pair might affect the resultant sex (one of the remaining two sexes, perhaps) and its physical capabilities, as in the caste system suggested above.

Otherwise, perhaps they have a more complex genetic system than that of Earth creatures: each sex provides one of: half of a DNA-analogue strand; an "interpreter" cell that acts as a sort of DNA-free egg, but which provides the biological "machinery" that interprets the creature's DNA-analogue, differences in which may affect the result of a given set of genes; a set of mutualistic symbiotes that affect the action of the offspring's organs, or perhaps even provide additional abilities.

Offspring are only produced if all four sexes take part in a mating; mating between two members of the same sex mix the shared reproductive element within the receiving participant, providing a means for evolution to act on elements like the symbiotes or "interpreters". Mating of two or three members of mixed sexes results in the received material being stored in the receiving participant or participants for a period, to result in offspring in the same individual is the receiving participant in a mating with members of the remaining sex or sexes.

It's way past my bed-time and I have work in the morning, so I can't properly contribute in this thread right now, but I'll leave a list of books that you may find useful:

- The Player of Games by Iain M. Banks features an alien civilization that has three sexes: 'male', 'female' and 'apex' (IIRC the eggs are actually provided by the apex, with the females acting more as incubators).

- Ringworld by Larry Niven has a similar species, where the females lay their fertilised eggs in the third sex, which in this case is non-sapient.

- The Left Hand of Darkness by Ursula le Guin is about a planet of people who have no sex most of the time, but go into 'heat' once a month and become either male or female depending on their current balance of hormones. It's the most different from your premise, but it focuses on the sex/gender stuff in detail, so it could be useful to you. Plus, everyone should read some Ursula le Guin.

edited 17th Jun '13 5:03:17 PM by imadinosaur

Humans are a species with more than one gender... they have two sliding scales, of feminity and masculinity, and simply their extremes would be:

• high-feminine low-masculine (so-called cis-gender female)
• high-masculine low-feminine (cis-g male)
• high-feminine high-masculine (androgynous)
• low-feminine low-masculine (agender)

"Sex" is not a dirty word :P

However, for the thing you were asking for... I once saw quite an interesting draft which was intended to create a biological basis for what humans would view as "male pregnancy" and included a third chromosome type, so -> X, Y and 0.

Sadly I do not remember where I saw it (it's been years)... could have been on Elfwood though. YEARS. There was the idea (IIRC) that Y0 individuals were born leaning female on the hormone balance, and had a one-shot pregnancy system which could not work after a delivery ever again, and who, after a successful-enough-pregnancy and shutting down of said system (IIRC) experienced a permanent shift in hormonal activity, gaining male fertility and function in the corresponding (pre-existing) genitalia.

X0 individuals were functionally female, 00... don't remember. Probably functionally female to maintain some balance, OR true androgynes with a multi-use pregnancy system as well as male sexual function, depending on long-term hormonal balance (again, to maintain some balance). Could have been "female until otherwide, change to male permanent" as well. Switching back and forth or being capable of double-function would be harder to explain AFAIK.

XX female XY male YY not possible (in case of anomaly, not viable?)

in addition: X0 female Y0 "one-shot" androgyne 00 true androgyne

Thus, a group with only XX and 00 would be able to reproduce, as before long some if not most of the 00 would turn male-active. Offspring would be all-X0 and could only reproduce with male-active 00s, in turn resulting in both X0 and 00 offspring.

With XY + 00 reproduction would again be possible with some-most 00s turning female-active. Offspring would be half X0 and Y0, both of which could become pregnant at least once, and with time all sexes would be possible (XX between XY and X0).

X0/Y0 + 00 — again, reproduction fully possible, situation would remain the same unless Y/X chromosomes were introduced by outside influence.

all 00 — reproduction all-ok, all offspring are 00

all Y0 — reproduction compromised, unless outside female function is found the group will die out due to limited pregnancies

all XX, X0 or XY - no reproduction