Emma Hilton Profile picture
Feb 4 10 tweets 3 min read Read on X
What an insane bunch of cherry-picked metrics, cobbled together to try and argue that trans-identifying males should be in female sport.

bjsm.bmj.com/content/early/…
There are little-to-no controls for physical fitness in the individual studies.

Yet they conclude: “transgender women do not exhibit significant differences in upper-body strength, lower-body strength or maximal oxygen consumption relative to cisgender women after 1–3 years of GAHT.”

You haven’t controlled for fitness!!!
Their "performance" data. Can you see one study that really sticks out as an outlier? Image
Alvares 2025, a study of 7 self-selected, trans-identifying males, who were 5cm shorter than the female comparators. Which is weird. The authors note this.

Also, they played lower level volleyball for about 30% of the hours put in by the female cohort. The authors consider that training volume and competitive level is, indeed, a confounder.
It's interesting when assessing lower body strength, this recent paper uses only jump heights and seems to ignore explosive power measurements.

That is, while acknowledging low-to-no control for fitness, they use a "fitness"" output instead of raw data like muscular power.

Why might unfit people not jump very well? Hmmm.
A spectacular pair of sentences.

Manipulating stats by adjusting for a sex difference is dishonest.
The bit about "not accompanied by increased functionality" is just riffing. They haven't provided evidence that functionality is impaired because they haven't compared like-for-like in terms of fitness.Image
I dispute "absence". Especially when you've ignored metrics like power (peak and relative). Image
They apparently ignore the second paper (Chiccarelli 2023) on an expanded USAF cohort, that showed advantages in push ups and sit-ups remain after two years.
Perhaps this tells us something about the cohort/type of data? Hmmm. Image
My friends, there is power data out there. Including in some of the papers you use. Image
Response from Alun Williams:

sciencemediacentre.org/expert-reactio…

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with Emma Hilton

Emma Hilton Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @FondOfBeetles

Jul 22
On Sinclair, SRY and the destruction of a legacy.

In 1990, Andrew Sinclair was the first author on a paper that reported the discovery of SRY as the gene that drives male development in mammals.
He was the first author on a paper led by Peter Goodfellow, and they published side-by-side with a paper led by Robin Lovell-Badge.

This pair of papers showed that the “mysterious make male mammals molecule” was the product of the SRY gene.

Unequivocally.
Their joint discovery was hailed, including by Sinclair himself, as the answer to one of the most fundamental questions about human life: what makes us male or female?

This is, IMO, an entirely reasonable lauding of the impact.
Read 21 tweets
Jul 21
I recently spoke at the 2026 International Working Group (IWG) on Women and Sport.

Here are my slides. Image
Sport seeks to identify and reward talent.

We want to find the best swimmers and the best boxers. Athletes with the physicality, skill and mental strength to win.

And we identify and reward talent by measuring performance.

But performance is an output, and not just of talent. Image
Nurturing matters. Environment matters. Having an athletic parent matters.

Nurture can obscure talent.

But differential nurture is, at least in principle, fixable. Image
Read 22 tweets
Jul 20
A thread on PMDS 👀

Persistent Müllerian Duct Syndrome is a DSD that occurs in 46,XY males with normal testes and normal virilisation, who also retain Müllerian structures (uterus, cervix, fallopian tubes, upper vagina) that should have degenerated in utero.
How does it happen?

Early in development, every fetus has two duct systems: the paramesonephric/Müllerian (female) and mesonephric/Wolffian (male).

(The formal names will become relevant later).
In XY babies, carrying the “make male” SRY gene, testes are made on schedule.

These testes make testosterone that promotes development of the Wolffian ducts, because testes will need an epididymis, vas deferens and seminal glands to do their fathering job.

The Selfish Testes. 🤣
Read 15 tweets
Jul 13
We wrote to Amnesty @amnesty @AmnestyUK about their reports containing defamatory slurs against Sex Matters and others.
So did For Women Scotland. @ForWomenScot
@ForWomenScot So did LGB Alliance @AllianceLGB
Read 21 tweets
May 13
On hantavirus #ANDV #hantavirus

I think the Andes hantavirus data is being misread right now.

Claims are circulating that the evidence doesn’t seem to support.

I want to walk through them carefully.
The 40% fatality figure: an artefact of who gets counted.

The 40% case fatality rate (CFR) figure comes specifically from hantavirus pulmonary syndrome (HPS), an outcome in a subset of hanta infections.

This is the severe cardiopulmonary presentation. It excludes subclinical infections that resolved without anyone noticing more than “a touch of flu”.

In Jujuy Province, Argentina, the seroprevalence (rate at which people have antibodies due to hanta infection) is 6.5%. Hospitalised HPS cases had a CFR of 13.3%, but most patients were described as having a mild clinical course.

Disclaimer: although an Argentine outbreak, this has not been confirmed as ANDV.

The 40% is the fatality rate among people sick enough to be diagnosed and hospitalised.

It is not the infection fatality rate.

These are not the same thing, and conflating them is causing significant confusion.
The true attack rate: barely any data.

The Boat had approximately 180 exposed individuals, and around ten cases have been detected. Three - soon to be four, I predict - have died.

Without antibody analysis of the full cohort, we don’t know how many mild or subclinical infections were missed entirely.
Read 21 tweets
May 7
On Hantavirus: a (non-technical) thread.

Disclaimer: I am a biology PhD, but not virology/epidemiology. Husbandman is a virology PhD. But I’m told I’m good at communicating science, so here’s my take.

#Hantavirus
Humans get hantavirus from rodents who carry it.

Some people went to Argentina birdwatching in a landfill, and were exposed to hantavirus because rodents like landfills.

Looks like one - if not two - people brought the virus onto their cruise boat.
So now we have an isolated boat with an index case: someone who is infected.

That’s not good for the index case. Hantavirus has a high fatality rate, and that’s scary.
Read 20 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us!

:(