SandChigger wrote:Redstar wrote:Although rare, identical twins can be of the opposite gender due to environmental factors affecting phenotype behavior or the deactivation of certain X chromosomes. Identical twins aren't exactly identical anyways, with a small percentage of "junk" genes that can influence final development.
Then Leto was the odd one, the result of "environmental factors" (like the contraceptive and excessive spice). You can subtract, but you can't add. (Where does the rest of the XX come from if starting out with identical XY males? Unless you assume abnormal XXY?)
And Paul foresaw a daughter, not a son.

I forgot about that prediction, so that is a hole.
SandChigger wrote:Redstar wrote:Not only that, but there is the possibility of half (or semi)-identical twins, which is the result of an egg splitting and both becoming fertilized by two separate sperm. The eggs would have identical DNA, while the two sperm have minute differences between theirs and, if one is XX and the other XY, could result in opposite sex identical twins.
You mean if one is X and one is Y ... if you're talking about the sperm. Right?
Either way, even two identical eggs + two different sperm = non-identical DNA.
But let's play it this way:
How much of that was known at the time Herbert was writing the books and could have been known to him? And is there any evidence that he was thinking of something so involved?
Yeah, I'm talking about sperm.
My point with semi-identical twins is that they share more DNA (around 75%) than fraternal twins (around 50%) and more than single-birthed siblings, which
might be enough male DNA shared in the female twin to produce a KH. I didn't mean that they had to be completely identical; just enough.
I should probably specify when I'm actually just speculating instead of seriously applying ideas to the Duniverse. In this particular case I started trying to find a possible scenario because some people think KJA meant Marie to be a female KH. Use some brains and figure it out in a way he obviously didn't. This is all just for fun, Chig.
SandChigger wrote:Redstar wrote:I would think that a breeding program encompassing hundreds of generations for the sole purpose of bringing about the unique capabilities of a KH would make such circumstances more likely.
Why?
Because the KH is a male that can accomplish things usually allowed only females due to biological and/or neurological differences (keep in mind that a KH is not only a male with dual-sexual OM, but there are no males with only one line of OM. So KHs are twice as unusual, unless there were male BG that could look back along their female lines and not male). So a breeding program to create the neuro-biological differences necessary in a male would possibly make other problems more likely, case in point Hasimir Fenring the "almost" KH that's also a genetic eunuch.
SandChigger wrote:Redstar wrote:In either case Ghanima would share the DNA it takes to be a KH and be a "true" female KH, ...
Really? In the second case the DNA is not identical; how can you be sure the important bits are shared?
That's why a "female" KH would be such a rarity. The important bits wouldn't always be shared, otherwise we'd have opposite-sex twinnings resulting in female KHs all the time.
SandChigger wrote:Redstar wrote:... or in an extreme and more likely scenario would only be biologically female, but have a neurological makeup somewhere between male and female. That neurological difference could be key.
Extreme
and more likely? Why more likely? (And if more likely, why extreme?)
If she were biologically female but neurologically in-between she wouldn't be a "'true' female" anything.
But explain "female KH". How would such a being differ from a "normal", male KH?
Under
these circumstances an intersexed birth could be produced with the male becoming the true KH (like Leto II) and the intersexed child being a semi-female KH. Obviously it wouldn't be a "true" female KH, but could be biologically female-dominant, but with a male brain. This would give the
appearance of a "female KH". This is more extreme because of the obvious results, and more likely because this happens more often than a purely chromosomal opposite-sex identical twin.
It could be speculated (we're still having fun here) that Fenring was a twin-birth with his male counterpart dying early in development and he himself being the intersexed child. Eunuch refers to an inability to reproduce through artificial means, personal choice, or
genetic fault. This could mean that Fenring is a non-reproductive hermaphrodite, with the outward appearance of male and neurologically female. This explains why he's a failed KH, and under the right conditions the opposite would happen and produce an outwardly female/neurologically male "female KH".
I have no idea how they would differ from a standard KH. That's for the fanfiction writers (or KJA in the epic revelation of the Marie ghola in
Throne of Dune 
) to decide.