Have I completely misunderstood GCSE biology...

@Cappuccinosisters

"However at the level of an individual, a person, there can occasionally be a mix of XX and XY cells in the body. I don’t think everyone on this thread was aware of that, it sounded like they weren’t anyway."

It's always better to be properly informed, so I at least thank you for speaking up on this matter!

"I should also add that a chimera doesn’t always arise because of twins fusing at a very early stage. That’s one mechanism but there are others, so the ‘mash of two bodies’ description isn’t always appropriate iyswim."

Yeah, I see what you mean, and I apologise for using a simplistic image.

I should also add that a chimera doesn’t always arise because of twins fusing at a very early stage. That’s one mechanism but there are others, so the ‘mash of two bodies’ description isn’t always appropriate iyswim.

Yes, I agree sex is binary in nature @Seethlaw. I already said that.

Usually an individual cell will be XX or XY, though occasionally they can be X or XXY or XYY or even more rarely XXXY etc.
And usually the (nucleated, somatic) cells in a person’s body will all carry either XX or XY (or occasionally XXY etc).

However at the level of an individual, a person, there can occasionally be a mix of XX and XY cells in the body. I don’t think everyone on this thread was aware of that, it sounded like they weren’t anyway.

But they never have neither, or both at the same time, or other. It's always either XX or XY: the inevitable sexual binary.
Yes, at the level of cells, (at least usually, unless they’re XXY etc as mentioned above).
At the level of a person it can get more complicated sometimes.

@Cappuccinosisters

"Anyway, for this and other reasons, some people can have be XX in some cells, tissues or organs and XY in others."

But they never have neither, or both at the same time, or other. It's always either XX or XY: the inevitable sexual binary.

"In exceptionally rare cases the literature has mentioned that both sperm and eggs seem to have been (possibly) produced in a single individual. I don’t know how that works in terms of hormones but some evidence of it has been reported, so…?"

So we shouldn't say that it's impossible for a single person to produce both sperm and eggs. That's true. In extremely rare cases where a single body is in fact a mash of two bodies, both part-bodies may end up producing their own organs. But each of those mixed bodies sticks entirely to the binary nature of sex. Even in the case of "true hermaphrodites", the ovary will be constituted of XX cells, and the testicle of XY cells. There's no deviation from the path determined by the cells' chromosomes. There can't be, because sex is a binary in nature.

I am sure some transactivists lie, as do all people, and for other TRAs their world belief just doesn’t align with reality.

There has been quite some misinformation posted on this thread too though. People seem to be unaware of rarer conditions, which isn’t too surprising. But if you’re not an expert in something then you shouldn’t use that subject to try to score points. That works both ways.

It’s not fair of posters to accuse a pp of lying when they describe their own perfectly plausible, albeit rare, medical condition. Is pp telling the truth? I don’t know, but they certainly could be.

What's more common, chimerism and mosaicism, or trans activists lying and appropriating other people's medical conditions

Just to add…you can get chimeras when both twins* are the same sex too of course, but they don’t have the potential to cause the same sort of problems in sex development. Identification using DNA tests can cause problems though. The Lydia Fairchild case, mentioned above, is an example of this.
(* there are other mechanisms by which chimeras occur also)

Possibly that poster ( @CosyLemur) is 46XX/46XY rather than 48XXXY though?
https://en.m.wikipedia.org/wiki/46,XX/46,XY

I think when people on here are talking about sex development and DSDs they often forget about chimeric and mosaic conditions which can affect the sex development of a very small number of people.

One of the ways these sort of conditions can occur is in the case of non-identical twins, one male and one female, fusing at an extremely early stage of development. Anyway, for this and other reasons, some people can have be XX in some cells, tissues or organs and XY in others.
Depending on the cell lines involved the sex organs may or may not be affected. Even when they’re not, it can cause confusion and complications (look up the case of Lydia Fairchild).

In some cases (extremely rarely) these conditions mean individuals can have an ovary and a testis, or an ovotestis. This is called true hermaphroditism.
“True hermaphroditism is a disorder of gonadal differentiation characterized by the presence in the same individual of both testicular and ovarian tissue.”
[Urologic Surgical Pathology]

In true hermaphrodites, fertility is usually compromised but there have been some pregnancies reported and even fewer instances of fatherhood. In exceptionally rare cases the literature has mentioned that both sperm and eggs seem to have been (possibly) produced in a single individual. I don’t know how that works in terms of hormones but some evidence of it has been reported, so…?

All this has nothing to do with trans people and sex is still a binary but it is complicated. I am GC but also a biologist and oversimplification (and accusing people of lying) doesn’t really help anyone.

😂 this is so beautifully and accurately put!

And women are disadvantaged when trying to argue the emotional case because we are seen as emotional and irrational and therefore our feelings and emotions can be dismissed

'GCs' have put the argument to bed - there is a fixed, biological definition of sex detemined by known genes (which in almost all cases are carried on specific chromosomes) that direct embryonic development along the Wolffian or Müllarian pathway. The courts agree, and have provision for evidential determination of sex if required for people.with the more difficult DSD conditions.

Unfortunately the TRAs have a shape-shifting, caffeine-fuelled toddler instead of a logical agrument, and putting that to bed is a different matter.

That exactly. Look at the flailing at the Cass report.

This is a movement rooted in feelings creating reality and in trying to control and bully everyone else into enablement. It cannot be reasoned with, facts and resistance are 'hate'.

You can’t put an argument to bed when someone doesn’t care about facts or listening to, when someone isn’t arguing in good faith but instead using emotions to carry their view

I’m not sure why GCs don’t put the argument to bed by stating chromosomes are how a persons sex can be determined (should there be any doubt).

More than 99.98% of people have xx or xy chromosomes. Of the 0.018% who don’t, many or most won’t have a trans identity. This group are the group where I think a ‘case by case’ basis might apply and having an ‘assigned sex’ might be appropriate

And kittens are definitely small asteroids.

All this isn't coming from anywhere rational, balanced and healthy. It never is.

I came across a TRA (TIF) on x claiming that endometriosis was an intersex condition

Yup. As a woman with PCOS I find this so fucking offensive.

PCOS an intersex variation?? wtf???

It's certainly possible to have extra chromosomes, but that doesn't necessarily extend the argument for 'sex is a spectrum'. After all, we don't usually consider Down's Syndrome to be part of the rainbow spectrum. At least not yet. Mind you, if you can warp PCOS into the rainbow, anything's possible.

0.02%

Totally.

This all got me musing about gametes and the differences between them, and whether it is theoretically possible, or will ever be possible, to make an embryo out of two ova or two sperm cells. I did a bit of reading, having not really thought about this before. Turns out it isn't possible, because they are not just containers for the DNA but also have other functions and structures that are complementary to each other. So both cells are essential for creating the embryo. You have to have one of one and one of the other for an embryo to form, they are not interchangeable. (And there is no "intersex" gamete). Pretty fundamental biological facts about the difference between the sexes. The sperm can "identify" as a egg as much as it likes (e.g. researchers can change its shape, size, move the genetic material into a different cell, paint it pink with sparkles), it still doesn't work biologically.

Randomly popping back to fish, bump headed parrot fish can definitely change sex. They also change skin colour. So if you first become a fish, you may well be able to identify as the sex and race of your choice 🤣. Unfortunately for the TRAs, no mammal can do the same.

https://www.barrierreef.org/news/blog/five-fascinating-facts-about-parrotfish

I found the stupidity astounding. Every human being, mammal, and many other species, require a male and female to reproduce. Every single human alive is here because of a sperm cell from a male and an egg from a female. This is early biology stuff.

No one is here because of two males or two females, only one male and one female. Intersex people exist, but are rare, and I’m willing to bet a very small number of the trans community are actually medically intersex.