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Any biologists here?

(31 Posts)
WTAFisthisshit Wed 29-Nov-17 19:45:37


I've lurked on Mumsnet for years and recently gravitated towards the feminist boards as it seemed to be only place where I found people with 'common sense' views.

You all seem to be very educated here so was wondering if someone could help explain to me what my daughter is currently being taught at uni.

She is studying psychology an is doing a biology module as part of it where she has been taught there are 8 different types of chromosome sex.

I was under the impression that xx = female and xy = male that there were rare instances of hermaphrodites and I was vaguely aware of xyy and xyyy which were still male but linked to violent offenders.

Does anybody know what this is and can explain it at a level that somebody with only secondary school science can understand and what the bloody hell it has to do with trans?

Thank you

Lancelottie Wed 29-Nov-17 19:54:24

It has nothing at all to do with trans. Your chromosomes are what they are, and will stay that way lifelong.

WTAFisthisshit Wed 29-Nov-17 19:56:46

I know that but what are the 8 different types she's being taught about? Is this an actual thing?

QuentinSummers Wed 29-Nov-17 19:58:55

There are different sex chromosomes in some organisms. For example, mammals including humans have XX (female) and XY (male). Birds have ZW (female) and ZZ (male). In some other creatures the female is XX and the male only has one sex chromosome - XO

In all species that reproduce through sex (as opposed to cloning themselves) there are only two sexes. The female produces eggs and the male sperm. So even though the chromosomes vary the mechanism doesn't.

The journalist Matt Ridley wrote a very accessible (but also quite old now) book about this called The Red Queen.

WTAFisthisshit Wed 29-Nov-17 20:01:24

OK, so are ALL humans xx or xy or are there variations? Does what she's being taught have any basis in fact?

GuardianLions Wed 29-Nov-17 20:05:23

Some intersex people are XXY and can have both ovaries and testes (but I think they are usually infertile). I don''t know about XYY.

Lancelottie Wed 29-Nov-17 20:05:24

According to the Wold Health Organization (random staid non-trendy source), people can have:

The usual XX female or XY male
XX male appearance (because a bit of Y chromosome stuck itself into part of the X)
XY female appearance (because something odd happened to the Y chromosome)
A single lonely sex chromosome X or Y
XXX female
XXY, XXXY or even XXXXY male
XYY male

and possibly some others further down the page

SadSongsAndWaltzes Wed 29-Nov-17 20:06:41

I'm not sure what they meant, but there are a number of sex chromosome disorders, where a person has sex chromosomes other than xx or xy. E.g. Single x is called turner's syndrome. Like you say, xxy is possible, as is xyy, xxx, and others. They vary, but can have female or male genitals, or be ambiguous. I don't think there are exactly 8 combinations though. It isn't related to being transgendered. How did your daughter explain it?

oldbirdy Wed 29-Nov-17 20:07:50

Xxy is klinefelter's syndrome.
X is Turner syndrome
Xx is 'ordinary' female
XY 'ordinary' male
Xyy is another syndrome whose name I have forgotten

Is that the kind of thing they mean?

Mycarsmellsoflavender Wed 29-Nov-17 20:08:51

You can also get females with XO ( just one X chromosome). it's called Turner's syndrome. They are sterile, as I believe are men with Klinefelters syndrome which is XXY. And as you mentioned you can get XYY and possibly other combinations with 4 sex chromosomes. I guess they would make up the 8 ( along with XX and XY obviously).

RafaIsTheKingOfClay Wed 29-Nov-17 20:12:51

I know of 6, but not sure about the other 2.


I don’t see any reason why there shouldn’t be at least 2 more. Is there a reason you think her university biology course would be teaching her stuff that doesn’t have a basis in fact?

Feelings Wed 29-Nov-17 20:15:20

This all sounds accurate to me, I studied biology.

WTAFisthisshit Wed 29-Nov-17 20:15:48

Thank you, yes I think that's what's she being taught about. But she said the teacher threw in a line about trans which disappointed her as she's fairly GC but feels unable to express it at uni.

I told her I thought these were all intersex and intersex had asked not to be conflated with trans? Is that correct? I also thought anybody with any sort of y was basically male, is that correct?

WTAFisthisshit Wed 29-Nov-17 20:17:13

I would like to think the biology course was teaching fact, I was just very confused when she said the teacher had conflated it with trans.

SelmaAndJubjub Wed 29-Nov-17 20:18:37

Hi WTAF . It's complicated!

Hermaphrodites are animals that have both male and female genitalia. This does not happen in mammals (including humans) but 'hermaphrodite' was sometimes used to mean 'intersex' in the past.

99.8% of people are either XY or XX. The rest have a genetic mutation of their sex hormones -the commonest of which is XXY (1 in1000 births). Most people who are neither XX not XY are unable to have children, as they do not produce eggs or sperm, but some can have children through IVF with donated eggs/sperm.

As well as the 2 in every 1000 people who are not XX or XY, there are also some people whose bodies do not develop genitalia normally because they don't produce the hormones that would do this, or the body doesn't respond normally to the hormones. The commonest version of this is androgen insensitivity syndrome. This is very likely what Caster Semenya, the athlete, has. With AIS, the person is male (XY) but their body does not respond to male hormones so their penis and testicles hardly develop and can be mistaken for a vulva and clitoris. However they don't have a womb and ovaries - they are male but with undeveloped genitals (I feel very sorry for Caster btw because she probably genuinely thought she was female and she has found out she isn't in front of the whole world). These hormone abnormalities are all pretty rare - probably only about 1 in 5000 births in total.

What does this all have to do with Trans? Absolutely nothing! And intersex people have repeatedly asked trans people not to drag them into their arguments.

Trans people try to use the existence of intersex people to prove that sex is not binary, but a spectrum. But this is nonsense. The fact that people are sometimes born with part of a leg missing doesn't alter the fact that humans have two legs! All it shows is that genetic mutations sometimes occur. Also, intersex people are not halfway between men and women. They are all either male or female, but with some differences caused by their different sex chromosomes.

Hope that helps?

Hastalapasta Wed 29-Nov-17 20:21:08

Any human with a Y chromosome is male, regardless of the amount of X chromosomes that they have. Hyper male and female traits come with XXY and XXX. Nothing to do with trans.

SelmaAndJubjub Wed 29-Nov-17 20:22:43

Some intersex people are XXY and can have both ovaries and testes

Not quite. Very rarely, humans can have gonads that contact both ovarian and testicular tissue, but they never have 2 sets of gonads.

It's incredibly rare - fewer than known 500 cases in the entire world since records began.

RafaIsTheKingOfClay Wed 29-Nov-17 20:32:55

Ah we crossed posts, you answered my question with your 20:15 post. I can see why that would confuse her.

WTAFisthisshit Wed 29-Nov-17 20:34:12

Thank you everybody that's great, I just wanted to check facts. She is open to GC thinking but she's also a teenager who likes to think she knows more than me at times and I'm aware that I and now arguing discussing things with somebody who has a greater level of education than me though not the life experience

pisacake Wed 29-Nov-17 22:44:54

Please direct her to intersex resources on why intersex has nothing to do with trans.

Intersex people 100% reject conflation with transgender.

There is NO genetic basis for trans.

Intersex = biology
LGB = sexuality
T = feelings

Datun Thu 30-Nov-17 08:23:49


The question I would be asking the teacher is, although one understands the fact that there are intersex conditions, can someone with XY chromosomes change sex?

Or can someone who is NOT intersex have a mixture of chromosomes?

It’s unbelievable that this teacher conflated it with transgender.

Someone needs to ask some very black and white questions.

scaevola Thu 30-Nov-17 08:32:39

"99.8% of people are either XY or XX"


NHS uses uncontroversial definitions of intersex and puts it considerably higher than 0.2%

Intersex is relevant, because a number of trans issues are being automatically handled in ways intersex is. So for example the athletics testosterone policy was drawn up very much on the basis of how to classify intersex athletes and had been running without controversy for years.

pisacake Thu 30-Nov-17 08:42:26

Did you actually even read the thread? AIS, is intersex, but XY. You can be intersex and XX/XY. Intersex also doesn't typically mean (as implied by some) that you are a hermaphrodite or something, it can be quite mild.

SelmaAndJubjub Thu 30-Nov-17 08:42:33

That's because non-XY/XX people are not all intersex people. See my explanation about hormones above.

The intersex society has good data here, although their figures include conditions that most doctors wouldn't consider intersex - for example hypospadias, which is just the urethra being on the underside of the penis.

QuentinSummers Thu 30-Nov-17 09:10:17

So for example the athletics testosterone policy was drawn up very much on the basis of how to classify intersex athletes and had been running without controversy for years
Haha, nope.
Testosterone testing was introduced after Caster Semenya started competing and has been controversial from the outset.
Gender verification testing has always been controversial.
The controversy comes mainly from intersex people - for example is it fair that a woman with complete androgen insensitivity syndrome (so male genotype, produces testosterone that cannot be used by the body so female phenotype) should be barred from competing? Most people think that is unfair.

However someone genetically and phenotypically male choosing to suppress their testosterone is not comparable.

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