okay - basic biology question...

What about the alligators? I need to know now! Do they have some weird reptilian way of managing all this?

Incubation temperature determines reptile sex, IIRC.

I don’t know why people talk about the birds and the bees because birds have WZ chromosomes and bees are WAY more complicated - though I love the term ‘haplodiploidy’:

en.m.wikipedia.org/wiki/Haplodiploidy

Transgender activist would be wise not to go down the hormone wash route anyway.

If it were true that gender dysphoria was caused by a hormone inbalance in the womb it would give us an objective test for transgenderism, thus negating the need for self-ID (just as brain scans for ‘pink’ and ‘blue’ brains would).

It would also mean that we could potentially ‘correct’ the imbalance in the womb, eventually eliminating gender dysphoria entirely.

Is this what they really want?

In truth there’s no test for a mismatch between sex and gender because gender is no more biological than your accent.

Oy, no blaming the education system here! We don't teach any tosh about hormone washes! Just standard x y crosses.

Alligators on the other hand...

What about the alligators? I need to know now! Do they have some weird reptilian way of managing all this?

Sperm cells are either X or Y and eggs are always X. At the point of conception the resulting cell becomes either XY (male) or XX (female).

The intersex diversion is such bollocks - its vanishingly rare to have a Disorder of Sexual Development, and as far as I know, no TRA or trans person has ever claimed to have one. Its very easy to check what chromosomes you have now in a simple test and presumably this is checked during the current gender reassignment process so it must be completely irrelevant.

The few people who have publicly stated they have an intersex condition dont claim to be trans.

presumably the hormone washes are country specific, so in the US, they know that girls play soccer, and in the UK, it's boys who play football, so cleverly manage not to get those particular washes mixed up. I mean, we all know what happens when a stray red hormone ends up in the white shirts load.

Another biochemist here. Assuming we are talking about homo sapiens all above is correct, X or Y determined by sperm. Alligators on the other hand...

The expression of gender varies over time and place so even if the hormone wash theory were true it fails to explain how the infant is born knowing that pink and sparkly=girl

Hot damn, I only just saw this thread. Biochemist here. And yes to all the sensible posters above.

Well, if you want input from another biologist: I'm seconding all the others on here. I'm even seconding the non-biologists. I haven't seen any outright nonsense yet.

Y'all are better than most classes of undergrads.

I love this forum.

I would have thought the TRAs would be all over this thread, explaining advanced biology to us. Strange.

I'm starting to think we may need to blame the education system...

Certainly there's a lot of neurotrash science around these days that really doesn't get challenged.

I cannot understand how trans activists can possibly say there is any “fluidity” in biology, because whatever is happening to the growing baby is always happening in an adult female human’s body. Can we acknowledge her? She is always an anonymous background provider in these discussions while in reality she is an objective reality and a unique individual and (most likely) the most important person in the new baby’s life.

that's a good point I hadn't thought of before.

Of course if we want to talk about hormone exposure in pregnancy leading to intersex conditions, I don’t think the research re effects of synthetic oestrogen in effluent water (off the top of my head...) will be very beneficial to the pro-transing side.

The effects of hormone containing waste on the environment are an argument against medical transition!

Hormone washes are, as far as this academic developmental biologist is concerned, nonsense.

There are conditions caused by inappropriate levels of maternal hormones - usually high T affecting baby girls.

The growing fetus will produce its own hormonal environment.

But ‘washes’ produced by Mum that exist to direct sex differentiation in baby? Nope.

That theory should be renamed the 'hormone hogwash theory'.

This is a really interesting thread.

It says a lot about the TRA organisations that they keep mentioning intersex, when repeatedly asked not to by people with intersex conditions. Tells you which group of people is the only group to be able to order others to pander to their identity.

She probably saw Kellie Maloney on Loose Women explaining the "hormone wash" theory - that's where I saw it, anyway

SRY stands for sex-determining region Y protein, so that’s a pretty good indication of what it does. It’s usually found on the Y chromosome but it can cross over to the Y and that’s what causes Swyer syndrome, where someone is ‘karyotypically’ male but ‘phenotypically’ female.

XX (female) and XY (male) are the usual karyotype. Karyotype just means your arrangement of X and Y chromosomes. Phenotype refers to how your genes are expressed, eg male or female, blonde, ginger, brunette, blue eyed, brown eyed, whatever.

TRAs will try to baffle you with XXX, or XYY, XO, and a bunch of other karyotypes, but they have nothing to do with transgenderism; they generally effect things like fertility, if anything at all.

Most XYY men will never even know because there are so few genes on the Y chromosomes that having multiple copies doesn’t matter. Years ago it was proposed that it lead to increased criminality but that’s horseshit.

make that 'because of a genetically caused hormone insensitivity' (this genetic problem was also programmed into the cells since conception).

You are correct that sex is determined at conception. However the differentiation of sex organs takes place some weeks into the pregnancy. If the SRY gene is present (on the Y chromosome), you'll get male anatonomy and the precursors for male gamete in the embryo, if there is no SRY gene, you get female anatomy and the precursors for female gamete (eggs) in the embryo. This differentiation involves 'hormone washes'. This is when everything goes right. Intersex conditions happen, when something goes wrong.

In case of intersex conditions, you might for example have the rare case that the organism is XY but is insensitive to the male hormones that play a role in differentiation. That may in the extremest case mean the body's cells are XY, but the organism develops a vagina and the baby looks like a girl (Swyer Syndrome). This condition leads to infertility. There are no functioning ovaries. The condition demonstrates well the difference between sex determination (XY) at conception, versis sex differentiation (in this case gone wrong because of a genetic insensitivity).

Intersex conditions are very rare and should not be used by trans activists of proof of anything. I think trans activists have sometimes used the language of treatment for intersex people. For example in the past before genetic testing (which these days can distinguish and clarify an intersex person’s genetic identity from a very young age) there might have been some confusion as to a baby’s sex and in those cases they would be “assigned” a sex which might have included surgery as a baby or child. My understanding is that is no longer considered appropriate or ethical and instead decisions on that individual’s bodily integrity should be made by them.

So the irony is that as we have grown to respect intersex people’s own autonomy and bodily integrity to make these choices for themselves, usually as adults, we are removing the same from children identified as “trans”.

Please correct me if my understanding of these issues is wrong. DH is a doctor and that is my understanding after discussions with him.