The Scientific American article 'The New Science of Sex and Gender' uses congenital conditions of the reproductive tract (DSDs) to make arguments about gender and identity.

Let's break it down to see what they get right and what they get wrong.

THREAD. https://twitter.com/MargaretAtwood/status/1280262917506641922

The article begins by explaining that biology is more complex than the XX and XY. This is true. There are rare developmental variations of the reproductive tract (DSDs) which produce chromosomal, hormonal, and genital anomalies.

"Many of us are biological hybrids on a male-female continuum," they write.

As evidence of this 'continuum', they utilize an exceptional case of a 94 year old woman having XY cells, and a womb in a 70 year old man, a father of four.

But let's look at these cases closer. The 94 year old woman, shortly after being conceived, likely absorbed part of a secondary zygote's cells, giving her some XY cells.

This does not put her on a continuum of sex because her reproductive system is organized to support ova.

Likewise, the 70 year old man with a uterus likely had a condition where parts of the Mullerian structure fail to disintegrate fully, sometimes leaving a vestigial uterus.

This does not put him on a continuum of sex because his reproductive system is organized to support sperm

Rather suddenly, the writers move on to the brain.

"New evidence suggests that the brain consists of a 'mosaic' of cell types, some more yin, others further along the yang scale," they write.

It's hard to know what they mean by this exactly, as they never explain it.

However, one aspect that sticks out is how the brain is masculinized and feminized to varying degrees depending on the level of exposure to specific sex hormones like testosterone and estrogen. Males will usually be exposed to much more T than females, for example.

This higher T exposure can change both the neuroanatomy and neurocircuitry of specific regions of the brain, such as the visuospatial region.

But sex hormone exposure and gene variance are just two reasons why you might see sex differences in the brain.

After presenting the two rare DSDs and the fact about the 'mosaic' of cell types in the brain, they claim that this 'continuum' of male and female affects "personal identity, health, and the economic well being of women."

And it is here where they present the thesis:

"That is because arguments about innate biological differences between the sexes have persisted long past the time they should have been put to rest."

Here, they conflate genuine sex difference research with bigoted 19th c. arguments about women's "inferiority."

They bring up an 1895 article (written by THEIR publication!) arguing that women shouldn't be allowed to ride bicycles because they aren't as strong as men.

Using a bigoted 1895 article and conflating it to sex difference research today is dishonest garbage.

Accurate evidence about biological sex differences in gene variance, the reproductive tract, and hormone exposure are important for many things, ranging from health to safety.

Studying such sex differences between males and females is not a value-judgment, as the article claims. The 1895 article was always and will forever be bullcrap, a complete caricature of the reality of sex differences.

And then the writers bring the absurdity of the 1895 article to the 21st century. They write:

"Yet as Scientific American's current annual in-depth look at a topic of pressing interest shows, embedded notions of women's inferiority persist well into the 21st century."

While it is true some backwards and regressive minds still believe that women are somehow inferior to men, most populations in liberal democracies, including sex difference researchers, do not believe this.

Most sex difference research is nuanced and well-produced.

We can definitely dismantle regressive stereotypes and expectations for both sexes, but the reality of biological sex and the presence of real sex differences is not bigoted, regressive, or illiberal.

The conflation of accurate arguments about sex differences with misogynist beliefs is concerning. But there's a reason Scientific American is doing this.

If they can produce an emotional reaction, then they can get others to believe that the category of male and female is not the product of biology, but rather, the creation of sexist and misogynistic researchers and regressive societies.

And if they can get others to believe that male and female are not reliable categories (and that we're all on a 'continuum'), then they can get you to believe that one's sense of self is the only reliable marker on both the personal and public policy level.

The ironic thing is...they end the article discussing the economic and social barriers for women's progress, while just having made the argument that the definition of woman is based in sexist and misogynistic notions, and that it cannot be reliably defined because of DSDs.

There's merit and truth to certain aspects of this Scientific American article, but its contradictions leave us with one question:

How can you liberate what you cannot define?

PS. I'll define it for you

A woman is an adult human female. And female is the sex which develops a reproductive system to support large gametes.

See, that wasn't difficult, nor is it bigoted to say so.

'Why Sex Is Binary'

And if you'd like to see an opinion from an evolutionary biologist: https://twitter.com/HeatherEHeying/status/1280536575420461057?s=20