The Planet with Three Sexes.

How could we build a world where the intelligent species has three distinct sexes? And no, I'm not talking about "in-between" sexes like bisexuals or shemales. These are three totally different sexes, and all three are required to procreate. Every newborn has three literal biological parents. Every normal relationship would be a love triangle.

But what would they look like? I imagine they would be mostly humanoid above the belly button and below the thighs. But how would their genitals be shaped?* How would their insemination work? Would all three have to be present at the same time to procreate, or could they do it in stages? Which one would bear the child to term? Or would they take turns, or would it be totally external?

What would the social conventions be of the three sexes? What would be their normal gender roles? We can't just have "the strong ones and the pretty ones," we'd have to come up with some sort of three-part division of stereotypes. Of course we will eventually violate these stereotypes, but first we must establish them.

And once we get all that ironed out, what kind of perversions could we give them? What would their taboos be? What acts could we create for them that would violate all their conventions and shame and embarrass polite society?

Once we have created this world, then we can start spinning strange and fabulous yarns about their loves, their affairs, and their cummings and goings.



*And how would they describe the opposite ends of a USB cable?

There could be the standard males, "ovulating hermaphrodites" and non-ovulating female birth mothers.

Reproduction would require males to copulate with a hermaphrodite, who then would impregnate a birth mother with his/her fertilized egg from his/her "appendage."
The hermaphrodite's appendage could be like a cross between a penis and clitoris.

Time to re-draw the anatomical chart illustrations!

Maidboy said:

There could be the standard males, "ovulating hermaphrodites" and non-ovulating female birth mothers.

Click to expand...

Hard part is devising a Darwinian explanation for the emergence of three sexes in that evolutionary stream. Trisexuality wouldn't have arisen only in higher lifeforms, but would be an ancient structure. I'd postulate a planet with a weird climate of variously toxic and nutritious compounds in the environment. Breeding males soak up certain chemicals, pass on their brewed semen to the ovulating hermaphrodites, and step aside while birth mothers are loaded with life.

But that's no fun. Bring on the three-somes!

In my version, there are two types of sperm, both of which are needed to inseminate the female. To make it more fun, both seeds must be planted simultaneously. The "third gender" looks female, but has a long tail-like organ that unrolls and slides up inside the female.

To make the "third gender" less "pseudo male" it has a womb & the inseminated egg is deposited in that womb rather than growing in the female's womb... the tail-like "cock" serves double duty by being used to gran the egg & draw it up into the "host".

Hmmmm, lots of good ideas here. But how about this: three hermaphroditic sexes. Let's call them A, B, and C for simplicity. All have both pussies and cocks, but in other respects look very different and have very different types of personalities.

To breed, first an A must impregnate a B. Then, in about a day (after the B's body has somehow processed the seed), the B must impregnate the C. And in about another day, the C must impregnate the A. The A will then carry the offspring to term.

If they sequence them too quickly (less than a day), the pregnancy will not take. If they go more than, say, two days, it will also not take. That is their natural form of birth control. That, or just not completing the sequence at all.

We also have six natural forms of "perversions" here: an A fucking a C or another A, a B fucking an A or another B, and a C fucking a B or another C. Fucking your own sex might be called homosexuality. Fucking the wrong "other"sex could be called, I don't know, maybe "cross-sexuality" or something like that. Since none can lead to procreation, they are all considered perversions. But naturally, forbidden fruit is always the sweetest, so......

Oh, another perversion! If, after the A>B and B>C phases are complete, the C goes and fucks a different A, what will happen? Maybe that's just a surrogate "mother" kind of thing. Or maybe it results in non-viable pregnancy. Or maybe, just maybe, it results in a tentacle monster! (you knew there had to be one eventually!)

Y'all have read Big Banana, right? Human siblings are transformed into banana slugs which are simultaneous hermaphrodites, each with a penis at one end and a vagina at the other. They happily 69 and shoot love-darts into each other.

Let's have a race of aliens who are somewhat humanoid -- but each has a penis at the groin and a vagina in the back of the throat. All sex is oral. Fertilized products are ducted to their sub-abdominal wombs for gestation.

But because of their unique biology [author waves hands to make it so] they must mate in rotating triad daisychains. Arbzz fucks the throat of Krznn, who fucks the throat of Trxpp, who fucks the throat of Arbzz. Then they switch around. This is necessary for each ovum to receive the required double-sperm dose. All become pregnant, of course.

I created a species like this Their three sexes are bearer, layer, and seeder. Bearers are basically female but do not ovulate, instead they have b-sperm constantly living in their womb. Culture-wise bearers are associated with business and running shops. Layers are the big, tall, territorial ones, but they have an ovipositor and produce an egg package almost the size of a ping-pong ball once a month, during their three day heat cycle. They like the outdoors, especially hunting and gardening. Seeders are the smallest (by weight; they're about the same height as bearers but they tend to weigh around 100 lbs.). They are the ones usually considered beautiful, and many of them are in the performing arts, though they also excel at politics and scholarship. They have a typical male set of anatomy, with the penis usually being slim. The typical way for a seeder to have sex with a layer would be for the seeder to put his dick inside the layer's hollow ovipositor (like it was a fleshlight).

These traits were inspired by various animals including hyenas (where females have a pseudo-penis), sandpipers (one of the only earth species where territorial females have male harems), assorted insects which have ovipositors, and spiders where the males produce sperm packets.

Hypoxia said:

Hard part is devising a Darwinian explanation for the emergence of three sexes in that evolutionary stream. Trisexuality wouldn't have arisen only in higher lifeforms, but would be an ancient structure. I'd postulate a planet with a weird climate of variously toxic and nutritious compounds in the environment. Breeding males soak up certain chemicals, pass on their brewed semen to the ovulating hermaphrodites, and step aside while birth mothers are loaded with life.

But that's no fun. Bring on the three-somes!

Click to expand...

Well this could be a planet where life began with three-part cell division as opposed to what us Earthlings have. A bit far-fetched perhaps, but no more than time travel or spacecraft moving faster than the speed of light, or any other sci-fi features.

Sex A has a womb that it can carry a child in during pregnancy.
Sex B develops an egg that it then lays inside the womb of A.
Sex C fertilizes the egg that has been laid by B into A.

Then A goes through pregnancy as the egg grows inside her.
Additionally, C may need to keep having sex with A and pump nutritious fluid directly into her.

p.s. didn't read the thread, it seems like someone already suggested something similar.

There actually ARE species in the world that needs an agent to breed. Especially plants. Some plants can't breed without an insect that will carry the spores from one plant to the other.

If you want it to be strictly one species, then imagine a breed that evolves from colonial animals like ants. Where there are workers, queens, soldiers and repletes as well as elates.

So build your race around a species that evolved with a colony/society where there were three distinct functions and "genders". One was a hunter type that was nimble and agile (b). It developed the egg based on its experiences. Another was thinking type that was slow but smart (b), and the third was a "queen" type that did almost nothing but was needed for breeding (a), so that B and C didn't need to waste time on pregnancy and child upbringing.

sunandshadow said:

I created a species like this Their three sexes are bearer, layer, and seeder. Bearers are basically female but do not ovulate, instead they have b-sperm constantly living in their womb. Culture-wise bearers are associated with business and running shops. Layers are the big, tall, territorial ones, but they have an ovipositor and produce an egg package almost the size of a ping-pong ball once a month, during their three day heat cycle. They like the outdoors, especially hunting and gardening. Seeders are the smallest (by weight; they're about the same height as bearers but they tend to weigh around 100 lbs.). They are the ones usually considered beautiful, and many of them are in the performing arts, though they also excel at politics and scholarship. They have a typical male set of anatomy, with the penis usually being slim. The typical way for a seeder to have sex with a layer would be for the seeder to put his dick inside the layer's hollow ovipositor (like it was a fleshlight).

These traits were inspired by various animals including hyenas (where females have a pseudo-penis), sandpipers (one of the only earth species where territorial females have male harems), assorted insects which have ovipositors, and spiders where the males produce sperm packets.

Click to expand...

That is a very well thought out piece of world building! Congrats.

Hypoxia said:

Hard part is devising a Darwinian explanation for the emergence of three sexes in that evolutionary stream. Trisexuality wouldn't have arisen only in higher lifeforms, but would be an ancient structure.

Click to expand...

In one of my stories the 3-sex arrangement is actually unique to the one intelligent species, while the standard for animals on their planet is hermaphroditism. The way this happened is that the proto-intelligent species split into two - like us and neanderthals. One of the two sibling species developed to become parasitic on the other; these ones had the ovipositors and were not capable of pregnancy. Then the two species reunited in one location, and the hybrids out-competed both parent species. The hybrid species initially had a mix of offspring that might or might not have ovipositors and/or functional wombs. Over several generations this stabilized into the 3 sexes that the modern species has.

While this kind of thing is unlikely to happen in nature, I think it's plausible enough for science fiction.

We can skip evolution and go straight to genetic engineering, and we needn't even leave Terra. The usual Mad Scientist (MS) devises a tri-sexual genetic system and breeds humanoids to it, preferably on a remote tropical island (so everyone can go naked) far from shipping lanes and satellite surveillance.

The nature of the 3-sex system depends on the original gender and proclivities of said Mad Scientist:

* If the MS is a pr0n-obsessed male, he'll give one sex a cock and the others pussies and boobs.
* If the MS is a bull-dyke, all genders will have vaginas but at least one long clit will ejaculate.
* If the MS is a swishy male, all genders will have both cocks and wombs. Tits are optional.
* A weirder (or more imaginative) MS will build gender-shifts into their infrastructure.

A lazy author could merely declare, "Hey, we got 3 sexes!" and let the group sex proceed, stroker-ish. Fun fun fun...