"This model of estradiol’s role in improving resistance to wound sepsis predicts at least four “sexes” across two treatment groups: females who are in the proestrus phase, females who are in the diestrus phase, females who are postmenopausal, and males."

This is Sarah Richardson, of the Fuentes review.

Four "sexes", three of them female and the other male. JFC.

Also in the frame as new sexes, fat men, pregnant women and children. JFC.scholar.harvard.edu/files/srichard…

An interesting article from Professor Andrew Sinclair here, criticising World Athletics proposals to SRY screen their elite female athlete cohort.

It’s a classic. Arguments from authority. Cherry-picking. Doesn’t appear to have read the policy. theconversation.com/world-athletic… A half-truth.

Apparently-female athletes who test positive for SRY will have a consultation with WA, with a view to medical assessment to better understand any medical conditions (DSDs) they have.

It is this diagnosis that will determine eligibility (or not).

Ok.

Let’s take Kelly’s penalty at 110 kph and Isak’s belter as 108 kph.

First up, Isak’s belter was from outside the penalty area, under defensive pressure, on the run and without perfect body positioning.

Compare.

https://twitter.com/fondofbeetles/status/1949905387181818276

That Kelly put 110 kph on a penalty is astonishing. That Isak managed to get 108 kph out of this belter is astonishing.

Isak could put 110 kph on a penalty with his eyes closed. Kelly will never get 108 kph on a 20-yard shot she digs out from under her.

No shade.

Five years ago, I gave a speech comparing sex denialism to creationism.

At the time, my partner-in-crime, Colin Wright, and I were near-lone academic voices willing to stand up and say “Biology! We have a problem!”

@SwipeWright Reflecting, back in 2020, on that state of affairs:

“[That] there are two sexes, male and female is apparently something that biologists do not think needs to be said.

I think they are wrong.”

It took Naomi Cunningham a single minute with a medic under oath to get a straight answer to a question that nobody wants to answer. Crickets.

"My data has suggested that my power, strength, stamina, muscle mass, oxygen levels and lung capacity all fit within the c*sgender female range."

Let's look at why this is a red herring.

onmanorama.com/sports/cricket… Several people argue that if the metrics of a trans-identified male fall "within female range", it is fair for that male to compete in female sport.

But we need to look at what's typical .v. what's exceptional.

Let’s address what many consider an uncomfortable topic.

Here, Bunce argues that Khelif was “condemned on her looks”.

That’s not true.

https://twitter.com/bigdaddybunce/status/1928704857336168626

People argued that Khelif appears to be male.

They may not have always been as polite as Bunce’s sensitivities required, but this is not “condemning” someone “on their looks”.

It’s noting that Khelif looks male/masculinised/(a man, if you prefer), and raising urgent alarms about what that means in boxing.

I don't think this is The Solution, but I'm generally in favour of weighing up proposals, so let's look at this one.

California high school sports have proposed to protect girls and accommodate trans-identified boys as follows:

If a male athlete gets a medal, the displaced female athlete also gets her medal.

Some thoughts to follow, chewing the fat for open discussion... An example of finish places and medals under this scheme might look like this:

1st William-now-Lia 🥇
2nd Helen 🥇
3rd Sarah 🥈
4th Catherine 🥉

So on the face of it, the top three girls get their rightful medals. Presumably this is how CIF say they are protecting those girls.

This is a computer-generated series, transitioning between "hyper male" and "hyper female".

Where does your perception of the sex of the person shift?
Which face is the most ambiguous?

If you reply, please include your sex (the actual one). OK, in the paper, the data was:

Faces 1-3: 100>97% scored "male"
Faces 5-7: 94>100% scored "female"
Face 4 was the transition face, with 68% scoring it "male".

FTR, I didn't hesitate on 4/male then 5/female.

This is the menstrual cycle.

Trans-identified males do not have one. This is the uterus, from which we bleed.

Trans-identified males do not have one.

People with 5ARD are male, not female

In defence of Semenya et al, many argue:
1. athletes with 5ARD are female;
2. features associated with 5ARD are normal female variation;
3. these athletes should be included in female sports.

The first claim is incoherent. To understand 5ARD, let's look at healthy reproductive development.

Both male and female development are well-understood.

“Sex screening in athletes is racist!”

Why? Really struggling with this.

In our recent paper (cited by World Athletics @sebcoe) calling for the reintroduction of sex screening in the female category, we make it very clear that this type of screening must be:

1. Cohort-wide | performed in all athletes wishing to enter the female category, regardless of skin colour, religion, nationality etc.

2. Early | to protect privacy and dignity, and avoid athletes being front-page news.

With these parameters in mind, the sex screen itself cannot be considered “racist”.

onlinelibrary.wiley.com/doi/epdf/10.11… Citing historic ethical issues won’t wash. We all acknowledge these. Early, cohort-wide screening will avoid the failures of the past.

So the cry of “racism” must be aimed elsewhere, presumably anchored on the premise that previous targeted screening (which is precisely what I and others advocate against) brought multiple black athletes and very few white athletes to our front pages.

In sport, we are interested in the effects of male or female development on the body, not the booty.

The category boundary between males and females is male-pattern androgenisation - having testes that make testosterone (T) and a functional T response. Disorders of sex development (DSDs) affect reproductive development, and sometimes challenge legal and social sex classification.

5ARD, for example, means a male baby doesn't make the hormone required for penis development. The baby may be misclassified as female at birth.

On “we all start as females” (by request).

At the level of anatomy, “female” describes a particular reproductive system - eggs in ovaries, oviducts, uterus, cervix, vagina and vulva. This reproductive system begins to differentiate at around six weeks post-fertilisation, when the embryonic gonads - two balls of cells clumped in your pelvic area - turn into ovaries and not testes.

I ran a fairly straightforward analysis of track and field performances across junior ages in different track and field competitions.

The raw analysis looks like this for international records. Above the line is male advantage, below the line is female advantage.

This pattern its repeated across national and state-level competitions. You can see that for almost all events at all ages, boys hold advantage over girls.
Where female advantage is detected, this is easily explained.

At 10 years old, girls grow ahead of boys, and catch up/overtake them briefly in running.

The female advantage in discus at 15-16 years old is because girls throw lighter implements.

The distance drop off as boys move to the 2 kg discus is obvious.

Hello @michaelshermer

Please see the following links to various papers and commentaries I and others have published on sports categories.

Please follow me (obvs 😂), @TLexercise @Scienceofsport @runthinkwrite @cathydevine56 @BrowngaGreg @MaryOConnorMD @DrMJoyner and associated scientists for academic work.

Guys, add your papers below please. Where it all started (academically): “the muscular advantage enjoyed by transgender women is only minimally reduced when testosterone is suppressed.”

There are a couple of letter responses linked to this too.

link.springer.com/article/10.100…

Let’s have a think what hormone categories looks like. And let’s assume that @neiltyson is considering a high/low T category. This has also been proposed by @AliceDreger

Thanks for the shoutout, Colin @SwipeWright

https://twitter.com/swipewright/status/1865631106252382617

The proposal only works if you don’t deny evolution and sexual selection. Remarkably, there are academics who argue there is no biological basis for why males run faster than females. While it is plausible ongoing underinvestment in female sport means female athletes have not yet reached their full potential, it is frankly ridiculous to think this can explain the entirety of the performance gap.

See Sheree Bekker et al for more details on why, because one time, this one female figure skater won a medal, Usain Bolt should be allowed to race against females.

Why male advantage in sport is not a social construct: height.

Height is a key difference between males and females. What is nature v nurture? What does that mean for sport? Bigger skeletons are most obviously driven by longer bone growth. Key bones like those in your thigh (“long bones”) grow from their end to get longer, making you taller.

Ok, my charity wears off.

Bekker’s presentation of the “Hilton and Lundberg” argument is nonsense.

At no point have either of us, or anyone else we work with, reduced male advantage to simply muscle mass/strength. @TLexercise @Scienceofsport

https://twitter.com/fondofbeetles/status/1855924222385643872

In the contrary, we have consistently argued that male advantage stems from many physical then functional outcomes of male development.

We spent hours (actually days 😂) creating this graphic, trying to highlight key areas of physicality that underpin male advantage.

HowTF is this reduced to “it’s all muscle”?

I’m going to put my charitable hat on, and try to elucidate - maybe even, as good practice, steelman - an opposition argument.

Specifically, this one:

https://twitter.com/bjsm_bmj/status/1854863486129476058

Let’s set a concrete example: the 10 second barrier (100m sprint).

Wiki - allowing for small errors - tells me that around 200 male sprinters have broken it. We know, of course, that no female sprinter has been close (Flo Jo record 10.49s).

As the latest on Olympic boxer Imane Khelif is reported, a diagnosis of 5ARD is almost certain. I and others first raised the likelihood of this DSD a few months ago.

Understanding how the developmental biology of DSDs interacts with sports categorisation is crucial. I spoke about this with Andrew Gold during the competition: