to point out that one Y chromosome does not make you a male

[Nimbostratus100]

In response to other posts insisting that one genetic test and one Y chromosome makes an athlete indisputably male with no room for error, I just want to point out that it not true.

There is always genetic exchange, for example, between a mother and baby, so anyone who has had a son will still have Y chromosomes in some cells in their body, and that will possibly show up in a genetic screening.

I am all for keeping men out of women's sport, and defining them genetically, but please lets not go over the top - one test does not prove you are male

I think you need some biology lessons. That’s not how it works.

I assume OP is talking about microchimerism.

Are you claiming that women's chromosomes change from XX to XY/ XXY if they have a male child?

This is going to go well.

@CatsGinAndTwiglets yes, it does. Microchimerism is an established and reasonably well understood phenomenon. See here https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2633676/ However, this is not what is generally meant when discussing whether or not trans people should compete in sports.

Er, do you not think they are aware of that when they do the test? That's why they test specific types of cell like epithelial cheek cells. I have 3 boys so there is quite likely the odd cell with a Y chromosome floating round in my bloodstream, but, while they cost me a lot of money, I don't think their chromosomes are invading my cells and integrating with my DNA, like some kind of marauding virus!

Good effort, @Nimbostratus100, but blood tests do not sample one single cell. Microchimerism is just that - micro. A few foetal cells that made it across the barrier that's supposed to keep them out (which may prove something of a theme in this thread!)

Keep reaching for ever more arcane theories on why we cannot define a woman.

Best not to use a 15 years old reference to prove a point. Has this work been replicated more recently? Have other authos come to the same conlusion since 2007? If so, please direct us to the research
Also, this is, as are many similar studies, in the murine model. so not necessarily applicable to humans

I am a geneticist, and that is exactly how it works

this is exactly what I am pointing out, they do, and could well appear in your cheek cells

@NQOTDarling
First reference from Google. Here are some more recent ones
https://www.sciencedirect.com/science/article/pii/S2589004221016345

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6714269/

Honestly, this is a thing. However, as I said, it doesn’t make the point the OP thinks it does.

So they could randomly appear in every single cheek cell that was swabbed, while non-chimera (ie your own) cells were miraculously avoided?

I am all for keeping men out of womens sport, but ignorant hysteria does not help in any way, shape or form.

Abuse directed at an individual WOMAN because of a Y chromosome being detected in genetic testing is just repellent.

Effectively we’re discussing “one drop” policy ie a single Y chromosome does not make you a man, especially if you’ve had male babies/had a male twin. However, that isn’t really the issue at hand?

no, the issue at hand is people reacting out of ignorance to genetic testing of athletes, and acting as if it is so cut and dried that one test can be definitive, when it might not.

Looking and acting stupid does not help

Sometimes it takes more than one test, and sometimes it takes time

There's got to be a line somewhere - surely that's the point of testing in elite sport?

yes. All your cheek cells are clones of each other. If the original of a cell line, 1, or 5 or 30 years ago, had a male chromosome, all the decedents would too.

I'm also a geneticist, what a surprise, and that is not how it works. They aren't integrated into my cheek cells and that's not what that study says. Genetic testing is perfectly aware of chimerism artifacts and finding 1 Y chromosome in sample from a woman that was 99.999 % X X would not lead to a diagnosis of male!

Exactly, but my point is, that the line is not necessarily one test, and the level of ignorance shown in people insisting that one test is all it takes, is unhelpful, and does nothing for our cause

Ummm, if you've carried and birthed a baby boy...I would say that has cleared up any question of "are you male or female?" anyway...surely? I am not a geneticist though.

If all is mothers of sons are sporting all these Y chromosomes - how come none of us are walking around swinging our penises between our legs?!

You know exactly why and how males and females are defined by sex and why they are segregated in sports categories.

We really are spitting the tiniest of feathers now over this 🙄

but it takes time and testing, that is what I am saying. YOu can get a sample when there are Y chromosomes, and you need to take another sample and test again.

Lol - best post in the thread!

In forensics, it is well known that getting a sample with Y chromosomes in a DNA test does not necessarily mean you have DNA from a male, it is going to be the same in screening athletes.

Grasping at straws much?