OK we have men and women, (male and female) pretty easy so far.
I was reading in Wikipedia…
OK I guess I am trying to visualize a “third sex” and having problems with that concept. I never really thought about it before.
So if we had a third sex, what could it possibly be like?
I’m fascinated by species that have a sex that is completely different in form than the other. It would be cool if we had a 3rd sex that was like a giant caterpillar or mollusk.
Some jokes write themselves.
In Piers Anthony’s (I KNOW, okay? But his non-Xanth stuff is occasionally pretty good) Kirlian series, the Spicans were a triple-sexed species. The third sex was a sort of catalyst whose presence was necessary along with the “father” and “mother” genders to actually produce an offspring.
Also, Asimov’s The Gods Themselves has aliens known as the Hard Ones and the Soft Ones. The Soft Ones have a three genders:
There’s somewhat of a mistake in that Wikipedia article: The existence of a third sex would not necessarily imply the existence of a third type of sex cell. There are fungi with over a dozen different sexes, but you still only need two at a time to mate (any two of different sex can produce offspring).
As I recall, some fungi exist in several genetic forms…quite a few more than two different forms. Only certain genetic forms will fuse with others (think union of sperm and eggs), so you might call these different sexes. Sex can be considered the union of genetic materials from two (or more) different individuals.
Additionally, there are any number of fungi that have several different forms in a life cycle. Wheat rust is an example as I recall. Each stage looks and acts differently to reproduce.
Sorry, but it has been 40+ years since I studied this, so I can’t be specific in the details, but it can be found by googling fungi life cycles. As an example take a look at http://www.lclark.edu/~seavey/bio210/wheat_rust_l.c.html
Some of the so-called algae have even more complicated life cycles.
Actually, bees, ants and other colony insects - have the best example available to us on our own planet of species with three genders. Of course, one of them is neuter. Not, I think, what the OP had in mind.
The Gods Themselves is the best example I can think of - and it won the Hugo - SF fandom’s highest award - the year it was published. But there are very interesting treatments of other methods of reproduction by Ursula K. LeGuin (also a Hugo winner) and James Tiptree, Jr. (a nom de plume) wrote “Your Haploid Heart” about a different reproductive alteration in humans from that hypothesized by LeGuin. It was collected in Star Songs of an Old Primate While this story didn’t win any awards (more’s the pity, IMO; I think it’s a great story), Tiptree was another winner of many awards and honors. IIRC, another story of hers which did win a Hugo was the first prominent story by a good (i.e., respected by their peers) writer which featured cloning as reproduction; it was “Houston, Houston, Do You Read?”, and was first collected in Aurora: Beyond Equality
Larry Niven’s Pierson’s Puppeteers have a “third gender”, but they’re extremely reticent about their method of reproduction. I can’t recall in which story it is revealed, but a Puppeteer reveals that the third gender is non-sentient. The protagonist in that story gets the impression that it’s actually a host animal in which the puppeteer embryos grow and develop in much the same way as some earthly insects (and arachnids? having trouble recalling) parasitize other species by laying their eggs in them. Ringworld, the first novel in which he included a puppeteer as a character, was yet another Hugo winner, by the way …
<snark>I’m not recommending anybody of Piers Anthony’s caliber, you see.</snark> 
Perhaps yet another SF fan will be able to think of other examples. I don’t think Octavia Butler’s work qualifies, as it features inter-species reproduction. It is, however, highly regarded, and she, too, won awards.
Actually, she was the one I first thought of when I read the OP. If I recall correctly, the inter-species reproduction was actually an adaption of the aliens’ three sex reproduction. In that species, there was a male, female, and a third sex whose name escapes me. The male and the female (who never touched, even casually) only had sex with the third sex, who mixed the genetic material and implanted it into the female. Once the inter-species part came in, they added an additional human male and female to the family, who also only mated with the third sex.
On Alien Nation, two different forms of male were needed to fertilize and catalyze the female for conception to occur. The third gender, known as a binnaum, comprised a very small percentage of the population.
Tenctonese.Scroll down to “Reproduction”
I think Frank Herbert’s Bureau of Sabotage works have a third gender. But it may simply be a third life stage of some sort–it’s been a long time. Given my uncertainty, I probably shouldn’t post–but I think the “The Tactful Sabatour” may be useful in dealing with how a three gender species might interact with a two gender species.
The Wikipedia article is talking about different sexes at the gamete level. I doubt there’s much you can do to elaborate on the “sessile ovum, motile sperm” arrangement. So genetically, I don’t think there’s any way to interchange genes between more than two creatures at a time, at least not beyond the fungi/algae level. As has been pointed out, there’s a tremendous amount of possible variety at the organism level, but that’s more in the line of reproductive strategy, not a true third genetic sex.
In The Star Beast, Heinlein (speaking through the mouth of one of the main characters, as is his wont) notes that the Hroshii come in six assorted sexes – but doesn’t get into any detail beyond that.
Lummox was female, more or less
Larry Niven’s Puppeteers have three genders - a female and two types of male - both of which are required to impregnate the female. It turns out though that the female is an entirely different species and serves as host to the parasitic embryo - a parasitic (or perhaps symbiotic) relationship.
:smack: :smack:
Ohgawd, you’re right. It’s been too long since I reread that, but it’s behind a whole stack of boxes I can’t move. Of course, she was more important than anybody knew, but … I won’t add any real spoilers.
You consider the alien translator a main character? I wouldn’t have. None of the humans had a clue about that species. I thought the aging bureaucrat was priceless, and loved how he managed (almost) everybody.
Y’know, I’ve always wondered how they’d be able to make the changes in the title character that they were planning at the end of the book. Oh, well, they were aliens - very strange ones, at that. I really miss that old man, even if his writing did get kinda weird those last few years. And I’d absolutely love to know what his reaction would have been to Cordelia Naismith Vorkosigan.
Wouldn’t a third reproductive gender to be evolutionary viable need some way to get it’s chromosomes in the action too?
Which would mean a three gender species would likely produce young with 3 sets of chromosomes.
What form that 3rd chromosome set would be delivered I can’t hazard a guess.
Well, the way I envision it is as follows for genders M, F & T:
There are only two chromosomes involved in determining gender. These chromosomes match up as:
MM, MF, MT, FF, FT, and TT.
Homozygous individuals clearly have only one possible gender, that is MM = M, FF = F, TT = T. The gender of heterozygous individuals depends on in-utero hormonal triggers. Thus an MF individual can have either the M or F gender depending on the pre-birth environment. (Alternatively, heterozygous individuals have distinguishing sexual traits–color, hair patterns–that indicate they can switch gender at will. This makes them highly desirable and there is much discrimination against the homozygous–see HoZy Anti-Defamation League.)
In “nature,” viable offspring can only be produced by the mating of individuals of two different genders. If an MF (gender M) mates with a TF (gender T), they could have an FF (gender F) child.
Of course, it might be different. Perhaps T is always dominant, but there is a smaller frequency of this allele. Perhaps any coupling can produce viable offspring, but there is a cultural aversion to same gender pairings. I can even imagine scientific break throughs such as invitro fertilization for same gender couples resulting in viable offspring and much social unrest.
Or am I just being silly?
I believe Permanent Undersecretary Kiku so described the Hroshii when speaking to Ambassador Greenberg, but I could be wrong.
Mr. Kiku is one of my favorite Heinlein characters/mouthpieces. Certainly the characterization belies the frequent charge that all of Heinlein’s heroes are alike - if Heinlein can make a government bureaucrat not only heroic but likable…
The Azad in Banks’ The Player of Games had three sexes. The apex sex was dominant, with the males and females subordinate. This was in stark contrast to the Culture which had only two sexes and was totally egalitarian. In fact, the inhabitants of the culture could change sex and sometimes did.
It should be noted that if we ever do meet aliens, it’s virtually certain they’ll have two sexes. Having two sexes has a disadvantage (you need two of different sexes to reproduce – if there’s none of the other sex around, you’re out of luck) but its advantage (gene mixing) outweighs it. With three sexes, the disadvantage (needing three different sexes) outweighs the advantage (more gene mixing).
The Kurii, occasionally-necessary aliens in John Norman’s Gor books, had three sexes (possibly four depending on how they’re counted… bear with me a moment). The sex that ovulated wasn’t the sex that gestated - males impregnated egg-carriers, who then passed the zygote on to blood-nursers, and the offspring could be any of these. Within the males there was a distinction between “dominants” and “nondominants”, a differentiation that apparently existed from birth, and only the former were allowed to breed; but in rare cases it seemed that a nondominant could be pushed around once too often and become a dominant. All this according to General Zarendargar, “Half-Ear”, who himself stated that even the Kurii disagree on whether this counts as three sexes or four, and expounded in Beasts of Gor.
I was actually thinking of the same thing. One could theoretically envision a triploid organism, with similar biochemistry as life on earth, only with 3 sets of chromosomes instead of 2. Cell division would involve triplication of each chromosome, and dividing into 3 daughter cells. Meiosis could proceed in triplicate as well, eventually ending up with 9 monopoid gametes for every cell you start with. There would be 3 types of gametes, say, egg, sperm-I and sperm-II, and fusion of all three would be required to produce a viable zygote. Ensuring that you only get one of each type of sperm would be more complicated than what we have to go through, but not outside the realm of possibility.