Tales of the Triploids by Imouto Kitten

Overview

The Triploids are an alien race native to a planet orbiting in the 
goldilocks zone of a yellow dwarf star roughly 15 parsecs or 49 light 
years from Earth. They are capable of perceiving and emitting 
electromagnetic waves in the bands traditionally used for over the air 
radio and television broadcasts, and such makes up a large part of their 
"spoken" language. As such, the names they use for themselves, their 
homeworld, and their parent star have no good equivalent in something 
perceivable to humans, though they have approved the terms Triploid for 
their race, Triploidia for their homeworld, and Solforme for their 
parent star. It is their innate ability to perceive radio waves that 
lead them to making first contact with humanity, intrigued by the 
earliest broadcasts that reached their home, though they naturally 
couldn't understand what had been encoded in said broadcasts.

The species were dubbed triploids by humanity for several reasons:

1. Their genetic material form a triple helix structure similar to the 
double helix of the DNA found in Earth-based life.

2. Their chromosomes are arranged in triplets, not pairs, and their 
zygotes are formed from the merger of three haploid gametes.

3. They have three distinct sexes, and the union of all three is 
required for procreation.

Physically, adult Triploids average between 90 and 120 cm in height, 
measured from heel of the foot to the scalp of the head with an overall 
body plan similar to humans, with waists slightly narrower than the rest 
of their torso and hips slightly wider, resembling an androgynous, human 
child in silhouette. Their skin is smooth and hairless, and comes in a 
variety of pastel hues. Unlike humans, where skin tone is a major 
indicator of ancestry, skin color for Triploids is much more mixed, and 
has never been a point of cultural division, though mated trios are 
generally of three distinct hues.

Their faces tend to be round or heart-shaped, with soft cheeks and 
chins, their mouths, which can produce not only audible sound, but 
infrasound down to 100th of a Hertz and ultrasound up to about 50 kHz as 
well as radio waves, are similar in appearance to humans, though they 
lack noses, instead relying on olfactory receptors in the roofs of their 
mouths. Instead of eyelids, their eyes are covered by hard, transparent 
coverings giving them a bug-eyed look. These natural goggle lenses often 
appear black, but sufficiently bright light reveals them to have a 
slight tint of the same hue as their skin. Their eyesight is 
hexachromatic, their cone cells coming in varieties with peak 
sensitivities that have lead to them being labelled infrared, red, 
yellow, green, blue, and ultraviolet from longest to shortest 
wavelength, though the red, green, and blue cones of a triploid don't 
perfectly match those of humans. Their Ears are pointed like traditional 
depictions of elves, and inaddition to having auditory sensitivity to 
match their vocal range, their ears also contain organs sensitive to 
radiowaves, though their brains interpret these frequencies in a manner 
closer to hearing than vision. Their scalps secrete a substance that 
sets into a protective, shock absorbing gel, giving them the superficial 
appearance of having hair. This gel generally matches the triploid's 
skin in hue, but is much more saturated in color.

Their skeletal structure is similar to humans, with a ribcage and pelvis 
to protect internal organs of the torso, arms and legs with two segments 
each, and 5-digited hands and feet with 3 segments per digit except for 
a 2-segment thumb and big toe. Their bones, however, differe greatly 
from any Earth life forms, being made of a strong, but light composite 
of biogenerated carbon nanotubes held together by a protein matrix. 
Their skeletal muscle is also significantly different, much less dense 
and with less strength per cross-sectional area. Combined with their 
short stature, this grants them very low body mass and makes them 
excellent jumpers, climbers, and acrobats, but are poor at lifting loads 
or delivering strikes. As such, they were traditional foragers and 
scavengers prior to domesticating the native flora and fauna of 
Triploidia and never managed to domesticate large herbivores due to 
insufficient strength to wrangle unruly individuals.

Triploids also have a series of air sacs throughout their body, and by 
raising their body temperature, can generate just enough lift to let 
them float just above the ground and their bodies can generate magnetic 
fields just strong enough to let them glide by pushing against the 
magnetosphere of Triploidia or Earth.

Though they have three distinct sexes, their trimorphism is low, with 
their genitalia the only distinguishing characteristic that is apparent, 
and while their race lacks a nudity taboo and generally only wear 
clothing amongst themselves if needed for protection, most have taken to 
whereing clothes when among humans, making it difficult to identify a 
Triploid's sex at a glance.

Though they have terms for their sexes and familial relations based on 
sex, the prevalence of radio waves in their language makes direct 
translation impossible, though they've agreed to humans using male and 
female along with associated terms for the two of their sexes that most 
resemble the two sexes of humanity, and have adopted the terms 
hermaphrodite and futanari as "good enough" approximations for their 
third sex, though terms for a herm or futa parent, sibling, parents 
sibling, or sibling's child aren't well-established, and within the 
native Triploid language, they also have sex-specific terms for cousins, 
and due to their race having three sexes, they have a concept of third 
and two-third siblings, grand parents of the herm parent's line, and of 
first cousins being single, double, or triple.

The Triploid sex commonly called male for convenience is the most 
similar to a human sex, possessing a penis that serves both for 
excreting liquid wastes and delivering genetic material and a scrotum 
containing a pair of testes, and aside from the testes producing haploid 
sperm from triploid stem cells, everything functions very similar to a 
human male. Compared to human males, a triploid male's penis lacks a 
foreskin and possesses a bulbous glandis and are generally less endowed 
than human males, while their testes are more sperical and are usually 
about the size of a ping-pong ball.

Triploid females also bare some resemblance to human females, with a 
vulva, clitoris, vagina, and uterus very similar to those of a human, 
and their urethras terminate at a small hole located between their 
clitoris and vaginal opening. However, their gonads bare more 
resemblance to testes than ovaries, and instead of a single pair of 
fallopian tubes, their gonads are connected to their uterus by a network 
of vessels that coat the uterine lining in a semen-like substance when 
female triploids orgasm.

The third sex, commonly referred to as herms or futas because their 
genitalia superficially resemble a vulva with a penis protruding from 
where the clitoris should be, have the least resemblance to a human sex. 
They do possess a vulva and vagina nearly identical to those of Triploid 
females, and their penis-like appendages do serve both for urination and 
for reproductive purposes. However, whereas the male penis is supported 
almost entirely by erectile tissue and is either rigid or flaccid, the 
herm's appendage, which is perhaps better described as an ovipositor, is 
quite muscular and very prehensile and the herm's urethra is capable of 
stretching to several times it's contracted girth without pain or 
discomfort, and even fully contracted, the ovipositor is quite a bit 
longer and thicker on average compared to the male's penis, and while 
the female vagina terminates at the cervix of the uterus, the herm's 
vagina terminates at an organ with no real analog in humans. This organ, 
which accepts ova from the herm's ovaries, secretes a thick, 
nutrient-rich substance similar to egg yolk into which the herm's eggs 
are mixed in preparation for procreation.

During a Triploid mating, the Herm inserts their ovipositor into the 
female's vagina and the male inserts his penis into the herm's vagina 
and the three move in rhythm to stimulate each other, the herm usually 
taking advantage of their ovipositor's musculature to stir the female's 
insides. When the male ejaculates, his bulbous glandis swells, trapping 
him within the herm's vagina and often, the herm's cervix will clamp 
around the collar of the male's glands as his semen mixes with the yolk 
and ova, partially fertilizing the ova and making the yolk congeal. Once 
the yolk has fully congealed, the herm pushes their ovipositor into the 
female's uterus and contractions push the mass of ova and yolk through 
the herm's ovipositor and into the female's uterus. An orgasm from the 
female adds their contribution to the mix of gametes and nutrients, and 
fully fertilized eggs feed on the yolk until the resulting embryos are 
developed enough to attach to the female's uterine lining, any gametes 
that failed to form a viable zygote dissolving into the yolk.

While the gametes of both Triploid males and females more closely 
resemble sperm and the herm's gametes resemble ova, it is not possible 
for two male sperm to form a zygote by fertilizing the same ovum, and 
female sperm are incapable of fertilizing ovum that have not yet been 
fertilized by male sperm.

Herms can be inseminated by a male and then retain the mass of 
congealled yolk containing partially fertilized eggs for a period of 
several days, though many find the experience unpleasant and the longer 
a herm goes without depositing, the firmer and less permeable to female 
semen the yolk becomes.

Triploids, having chromosomes organized in triplets, have three sex 
chromosomes in an individuals karyotype and three types of sex 
chromosome. The three types are generally referred to as X, Y, and Z, 
and children inherit one from each parent. Embryos with XYZ are 
non-viable and quickly become part of the yolk that feeds a brood in the 
earliest stages of development, while individuals with two or three 
matching chromosomes will develop into one of the three sexes as 
follows:

XXX, XXY, or XXZ: Female

YYX, YYY, or YYZ: Male

ZZX, ZZY, or ZZZ: Herm

Due to XYZ's non-viability, threesomes where all three partners are 
homozygous for sex chromosomes cannot produce viable offspring, and 
threesomes with only one heterozygous partner can only produce offspring 
of a single sex, and even in the best case, at least a third of zygotes 
are non-viable.