I am totally uninformed on this topic, but i’d like to know if any research and stuff has been done.
What kind of research are you looking for?
IIRC, some species of fungus have between five and several hundred mating types, which are rather analogous to sexes.
Kami_Bum asks:
Well, by a startling coincidence, I was recently involved in a discussion on this in another forum.
Let us offer some possible definitions of “trisexual”. Are there any species in which three different individuals offer one-third of the genetic makeup of a (triploid) zygote? No.
Are there species in which there are more than two sexual phenotypes? Yes. In addition to the fungi that DrFidelius mentions, we can point to social insects, which have a “two-and-a-half” sex scheme: males, fertile and sexually expressed females, and individuals that are genetically female but morphologically neuter. There are also certain analogies (though certain not identities) among mammals, ranging from mole rats to wolves to baboons, where a dominant pair of animals cause others to sexually and hormonally repressed, and dominate or monopolize the production of the next generation.
Could there be a trisexual (in the first regard) species? Well, monosexuality and bisexuality[sup]1[/sup] both have obvious advantages and disadvantages. Increasing the nummber of sexes beyond two doesn’t confer any additional advantages, so far as we can see. It might happen, somewhere, sometime, but it’s unlikely to be at all common.
1[sub]No comments from the tuppence-ha’penny seats, please[/sub]
[Moderator Hat ON]
Whatever this is, I don’t think it’s a Great Debate (at least right now). I think it’ll get a better response over in General Questions.
[Moderator Hat OFF]
My friends used to think TRIsexual meant that you were attracted to both sexes and animals…
We were only fourteen, IIRC…
:rolleyes:
The Tentonese aliens in the TV series Alien Nation required three sexes to make a baby. When George and his wife wanted another baby they needed the services of a third alien, the janitor Albert Einstein, who was neither male nor female but a “binnaum”.
Oh, you meant a real species? Well, never mind then.
No, no no no. It means you’ll try anything.
yeah trisexuals have to try real hard. I mean it’s hard enough getting laid with one person, just imagine if it had to be with two… it would never happen and the species would become extinct.
(Changed bibliophage’s bolding into an underline)
Actually, the Binnaum are male.
In the episode in question, George mentions that Binnaum are ‘less than 1% of [their] male population’.
I wondered if anyone would remember from Cheech & Chong’s The Corsican Brothers, the line about the famous “Marquis de Hickey” - the trisexual. Named thusly because,
“He’ll try anything. Mud, chickens, anything!”
If it’s science fiction you want, consider Ursula K. Leguin’s The Left Hand of Darkness – about the ultimate gender-bender planet. The natives were neuter most of the time, but every so often they would go through the phase of their cycle in which the same individual could turn either male or female, and reproduce.
Asimov had a story about this, I think it was called The Gods Themselves, it was a very intersting story and most of it was about how the three tried to have sex. One always wanted sex, one wanted children, and the last never wanted much sex.
This sounds right to me–similar principle to asking why two-eyed creatures are so common but three-eyed aren’t. There’s an obvious advantage to binocular vision, but the virtue of a third eye isn’t so obvious. Likewise, the shuffling of genes with two sexes is beneficial; what you add to that with a third is not clear.
On the science fiction angle, the Puppeteers of Larry Niven’s Known Space cycle were trisexual, but the process involved two sexes and a host in which the new offspring developed.
Even more obscure, Jim Aiken used the idea of three sexes in “The Lilith” and his novel Walk the Moon’s Road. Same general idea as Alien Nation (and a few years previously), but with a little more detail.
And the classic multiple sexes story was Ed Subitzky’s “Saturday Night on Antares, the Planet with 12 Different Sexes” in the National Lampoon.