Biologists take on sex seen in fab

[exmouse]

twitter.com/rebeccarhelm/status/1207834357639139328?s=21

Seen this floating about on fb
Any thoughts?

So true, Ereshkigal. It’s extraordinary the lengths they (TRAs, allies) go to. Almost as if they know they haven’t got a single rational, robust argument. Not a one.

Wow, now you say it, that's exactly what it's like.

CharlieParley I’m not academically smart at all, but I understood everything you wrote, so thanks for the info. and making it accessible

... lots of bowl haircuts... I’d managed to forget the horror of the bowl cut Zebra, cheers for the flash back

Okey dokey. I think we can safely say that pretty much every human on earth has one biological mother and one biological father. And those humans had one biological mother and one biological father. We exist because XX people and XY people mate and reproduce. Maybe there's some weird splicy thing scientists are trying in a lab, but doing some weird trick in a lab proves nothing. Sex. Is. Binary.

Xs and Ys are all that are on offer for humans banning an Isle of Dr Moreau scenario.

The reason I don’t have my students look at their own chromosome in class is because people could learn that their chromosomal sex doesn’t match their physical sex, and learning that in the middle of a 10-point assignment is JUST NOT THE TIME.

How likely is it that a university student of biology would be oblivious to the fact that there's something unusual going on with their chromosomes?!

Presumably you'd by this point have either a) menstruated b) ejaculated c) noticed & been alarmed by the absence of whichever of these you'd grown up expecting?

Someone mentioned up thread that periods are basically an infallible indicator that you are female. I'm guessing there isn't a DSD that allows for a functional sperm producing penis & testicles in chromosomal females, either?

& y'know biology students. People presumed to have an interest in how biology works?

Until now I've not been able to respond to that link because I didn't understand what it was saying. I'm shocked that experienced medical practitioners don't seem to understand either.

Responding to obfuscation (without being accused of bad faith for calling out obfuscation) is difficult!

I think it's interesting that the people using such amazingly convoluted props to claim that sex is not a binary are so willing to unquestioningly accept the idea of a "cis/trans" binary...

@Ereshkigal

And so the 'I sexually identify as an AH-64 Apache Gunship Attack Helicopter' was born.

I’m sure it would be very interesting to see how societal expectations change according to geography and / or time.
There is so much evidence of this. Anyone who has read widely or even been alive for say, 40 years has a wealth of examples.
The whole debate is toxic though because

1. there is NO evidence that chromosomal differences are related to transgender ism
2. it is only relatively recently that we have been able to look at chromosomes yet women have been discriminated against, mutilated and attacked just for being women for millennia. Put simply, being perceived as a man because you have a penis puts you in a better position socially whether or not your chromosomes agree (and 99.9% of the time they do).

Thanks everyone, glad I could help

The reason why it is difficult (and time consuming) to respond to this type of statement is because

a) many of us are still reticent when someone we assume is an expert pronounces on the science. (I keep thinking, I must be missing something, coz this seems wrong to me, but this is a biology professor?!) and

b) they usually write in an academic style that is designed to impress and shut down discussion, not to reach out to everyone. On first glance it often seems there's nothing wrong with their argument.

The only reason I can look at this now and see the flaws is because I've done so much reading on the issue and part of what I do for my clients is to read academic output and rephrase it into something more manageable for non-academics like us.

She could have done this herself, btw, all academics could, but academic language is designed to keep outsiders at bay.

And sometimes you need to really digest what they're saying to start thinking hang on a second...

Mathematically speaking it denotes not having a base of 2. Like the decimal or hexadecimal number systems.

I'm considering self-identifying as hexadecimal.
Binary is so last week.

Like with the tweet PurpleCrowbar is quoting. The prof's showing herself to be ever so kind in considering her students' feelings, but this is essentially as PurpleCrowbar says - 99.6% of females go through menarche, and the chances that any issues are caused by a chromosomal problem are minute.

Across Europe for instance, the frequency at which chromosomal abnormalities are discovered in pregnancies and at birth is less than 0.5%. Sex chromosome abnormalities are the fourth most frequent problem, but still make up only 5% of chromosomal abnormalities - that is about 0.025% of all babies tested, whether in utero or at birth.

These numbers derive from EUCAT. This is a European registry that includes about a quarter of all babies born across Europe as well as the results of prenatal testing. The sample size is about 1.5 million, so this is about as representative as it gets.

EUCAT includes children who presented with problems, and who were therefore tested before age 1. They don't account for children who are well and healthy and so never get tested until puberty. But because they include prenatal test results, which include fetuses later miscarried, died in utero and stillborn babies, the frequency of chromosomal abnormalities reported here is actually higher than in newborn studies.

Newborn studies test every newborn, regardless of whether they present with any problems or not. They typically find chromosomal abnormalities at a lower rate than EUCAT, at about 0.17 to 0.30% of live births.

However, the vast majority of children who have chromosomal abnormalities and never present with any problems have so-called balanced chromosomal abnormalities. Here two parts of a chromosome swap places, but no information is lost, so they typically do not present with problems. It's usually the offspring of these children who are at risk, because when their chromosomes combine with their partners, these misplaced parts can get lost. This leads to unbalanced chromosomal abnormalities, which do cause serious issues.

The most important thing to remember about chromosomes is this:

Chromosomes are not sex. They are not the definition of sex - neither in law nor biology. They are merely a mechanism which drives sex development. The starting point to be precise.

Which is why that prof is misleading people. Everything she points out there In terms of ooh sex is so complicated, there's like chromosomes and genes and hormones is a strawman.

In millions of years as humanoids on this planet and over 200,000 years as a species, we have not needed to look at chromosomes to know who is male and who is female. We still do not need it now. Because if we identify someone as male or female, we do so with better than 99% accuracy.

Sex is a description of a reproductive mechanism. This mechanism involves chromosomes at the start, then the SRY gene, then hormones which lead to the development of genitals along a predictable path, which then in turn produce hormones at puberty driving further development. Even abnormalities are predictable - we know what happens if any step of this mechanism fails.

That's why the definition of sex looks at the combination of chromosomes, gonads and genitalia. (This is how sex is also defined in law and why it is defined like that.)

That's also why different species whose chromosomal mechanisms differ from that of humans still have males and females. Because sex is a reproductive category - has your body developed the anatomy that typically produces large or small gametes?

You've got the anatomy for the production of large gametes? Congratulations, you're female.

You've got the anatomy for the production of small gametes? Congratulations, you're male.

How you get here is largely irrelevant. Wether your anatomy performs as expected is also irrelevant in deciding whether you are male or female.

And don't let these constant insinuations that our chromosomes might not be what we expect fool you. As Dr Emma Hilton (FondOfBeetles) reports from her own research looking at newborns and whether their sex chromosomes are not in line with with their sex - this is incredibly rare. 0.00017% kind of rare.

So if you know you're female, there's a 99.9983% chance you don't have a Y chromosome.

CharlieParley two massive thumbs up for a brilliant description which I would have undertaken myself but had so little energy when I read the Twitter thread I couldn’t get past just writing “it’s bullshit”

I found it particularly irritating that she used the term “non binary” when she meant intersex. Thus conflating people with congenital medical conditions which can have a devastating effect on their lives with a group made up largely of attention seeking teenagers adopting a meaningless label based on sexist stereotypes. Completely agenda driven.

All these threads are designed to make the science sound so complex that credulous people will conclude they don’t understand and that therefore they must take the word of the much cleverer person as truth.

It's an identical strategy to the one used by creationists. Biology is very very complicated, life is very very complicated, we can't possibly say life evolved naturally because it's so complicated.'' Now we have ''sex is very very complicated, so very complicated, we can't possibly say there are two sexes because it's so complicated,''.

Yes biological systems are complex but only absolute shysters will use the fact of their complexity to pretend it's impossible to describe them or make statements on how they came to be.

Good point HerFemaleness - there are definite parallels with creationists.

It's an identical strategy to the one used by creationists. Biology is very very complicated, life is very very complicated, we can't possibly say life evolved naturally because it's so complicated.''

Retro-fitting reality to fit your theory is what makes it complicated. Tangled webs and all that.

CharleyParley thanks, & you obviously know loads more about this than I do!

Can I ask a question?

If somebody had a DSD, to the extent of having chromosomes usually expected of the opposite sex, how likely is it that everything would appear perfectly routine throughout your teenage years, & then a post puberty chromosome check reveals a significant DSD, to the extent that you are in fact not of the sex you have always believed yourself to be?

If you're, say, 18yo, & at uni, is there any scenario in which you could have gone through an apparently normal male or female puberty & THEN discover from a check of your chromosomes that actually, they aren't what you thought they were? Or would there inevitably have been irregularities that would've made it obvious that things were amiss?

I think I get that there can be extra X or Y chromosomes which might not be an issue, & certainly don't suggest sexual ambiguity.

I'm really quite irritated by the suggestion that students doing routine Biology undergrad work might be in danger of sudden 'actually your sex is not as you've always understood it to be' discoveries if they investigated their own hormones, just because from a lay person's point of view that sounds terribly unlikely & therefore, unless there's loads more to it, rather undermines 'friendly biologist's' entire argument.

But as I say, I'm not a scientist. Is it really a possibility?

I've appreciated your clear explanations earlier - every day a school day!

Also, still nowt to do with people identifying as a different sex. I can understand how pissed off people with DSDs are with the appropriation.

they don't have chromosomes usually expected of the opposite sex in 99.999999% of cases. The mutations kick in further downstream of that. A common example is that they produce the correct sex specific hormones in utero expected from those genes, but there is a mutation in the genes that code for receptors for that correct hormone on the body's cell. So the baby then can't or can only respond partially to the correct signal of that hormone which would normally cause them to develop with standard male/female genitals.

So in these case you can get ambiguous genitalia which, ironically, is on a scale. So in rare cases, they can end up with what looks like completely the wrong genitals. This can often be corrected, to varying degrees, at puberty when there is a second hormone surge that comes from a different source where the mutation might not be present (why Caster Semenya looked more male after puberty). Or if not, it would become evident in almost all other cases at puberty that something other than normal development was going on. There is one particular DSD where a woman might not find out until infertility investigations.

Thanks - so highly unlikely that some poor freshman would get a huge surprise, then?

It felt manipulative & annoyed me more than anything else on that thread tbh!

Extremely unlikely.

It really is utter try hard, straw clutching bullshit isn't it! My brother sent it to me on FB because I'm critical of self ID. He's a scientist FFS, but also a woke bloke unfortunately.

The similarity to the organized efforts of creationists to persuade schools to let them "teach the controversy" is rather striking. Still evangelicalism, enlistment, recruiting members, is an inherent part of most belief systems whether religious or not.

The similarity to the organized efforts of creationists to persuade schools to let them "teach the controversy" is rather striking.

Yes, very much so. Eerily reminiscent.

If somebody had a DSD, to the extent of having chromosomes usually expected of the opposite sex, how likely is it that everything would appear perfectly routine throughout your teenage years, & then a post puberty chromosome check reveals a significant DSD, to the extent that you are in fact not of the sex you have always believed yourself to be?

The short answer to your question, PurpleCrowbar, and I'll refer you to my earlier comment here, is this:

Chromosomes do not define sex.

If you have perfectly normal female anatomy and underwent normal puberty, your sex would not be redefined by the discovery of a Y-chromosome. You would still be of the female sex, just an XY-female.

However, what the professor insinuates and what you ask here - perfectly normal development when chromosomes do not match sex - is extremely unlikely. So unlikely in fact that I would wager this professor isn't speaking from experience.

Here's the long answer:

So if your young student in this scenario had a perfectly normal female body at birth, went through a normal puberty, started menstruating, developing breasts and had no other issues, but then a check of their genes revealed the presence of a Y-chromosme, they would not then be considered to be male because they wouldn't be male. Male = male anatomy.

For a fetus to develop into a fertile male, you need three conditions to be met:

1. A Y-chromosome
2. A working SRY gene
3. A working androgen receptor (AR)

If the SRY gene isn't working, the result is an XY female - the determination of sex is here based on anatomy, which is typically female genitalia, but no ovaries and almost always no uterus.

These girls do not however experience a normal puberty and in the UK this would normally be noted, the child would be examined and once diagnosed, doctors would prescribe hormones to help pubertal development.

This is called Swyer Syndrome and extremely rare (0.00125% or 1 in 80,000 people are affected). It is even more rare, but women with this condition have given birth using donor eggs.

If the SRY-gene is working, but the AR is not working properly, the outcome is a person suffering from androgen insensitivity syndrome. Depending on whether the AR is failing completely, a lot or a little bit, such a foetus develops into a person whose external genitalia are typically female, typically male or a person with ambiguous genitalia (that is they are only partially masculinised).

A child with complete androgen insensitivity syndrome or CAIS is an XY-female, she has female genitalia, no ovaries and no uterus. With help in puberty she will develop female secondary sex characteristics.

A child with mild androgen insensitivity syndrome (MAIS) is an XY-male, with male external genitalia and may be fertile, although this often depends on taking testosterone. He will develop male secondary sex characteristics in puberty.

Neither MAIS nor CAIS children are likely to have a normal puberty without medical support, but can develop alongside their peers if this happens. Unfortunately, when puberty doesn't happen as expected that is often the time when the condition is first diagnosed, and this can often be more distressing than knowing about it earlier.

Children with partial androgen insensitivity syndrome (PAIS) are usually diagnosed at birth because they present with ambiguous genitals. Doctors will advise on the best course of action for the child and their parents then have to decide which sex they will raise their child as.

CAIS is rare, estimated to happen in 1 in 20,000 to 99,000 births.
PAIS is variously estimated to happen as often as CAIS or a little less.

There are no estimates for MAIS, but it is said to be less frequent than CAIS/PAIS.

Neither of these children would ever grow up to be the students in that zoology professor's scenario. The only condition I could imagine leading to a student being in this position is some form of mosaicism.

There is one reported case in the literature about an 46,XY-woman with normal puberty, who gave birth without any medical interventions. She has mosaicism but would be unlikely to be surprised by that Y-chromosome since her family had several persons with DSDs over four generations.

HTH

I read it. The biologist seems disingenuous. A truncated y chromosome with a deleted, mutated, crossed over or mosaically expressed SRY gene sounds like a disorder of sexual development. This is not transgenderism.
I think the same biologist posted a similar comment on FB and summarised with something like "humans can have xxy or xxxx chromosomes, rather than XX or XY. So sex cannot be a binary". Which is complete stupidity. Sexual binary doesn't refer to the amount of chromosomes, but their complement. You are either heterozygous for X (you have X and y, and are male) or you're homozygous (all X and are female).