That's an opinion piece from an anthropologist that doesn't cite any sources. A priori, if you're unsure, listen to the well-respected biologist talking about his field over a gender studies professor writing an opinion outside of her expertise.

But credentials aren't everything, so let's examine on its own merits. First off, it's largely based on the work of Anne Fausto-Sterling, who is deeply unserious and has admitted to publishing bullshit and backtracking by calling it tongue-in-cheek and ironic:

It's mostly about higher-level things like how sex is relevant to sports, though it's kind of a confused mishmash overall. It doesn't cite any sources, and doesn't really say anything, but here's a few relevant quotes:

If gonads were understood as the essence of sex, women who were phenotypically female but who had testes were men. This seemed illogical, so scientists proposed yet other traits

She doesn't cite anything for this, but she's incorrect. If you're phenotypically female but produce sperm, then you're male. There's nothing illogical about it. People with CAIS are male. Scientists aren't proposing anything of the sort.

Science does not drive these policies; the desire to exclude does. This intentional gerrymandering of sex opportunistically uses the idea of “biological sex”—which lends a veneer of science and thus rationality to any definition—to remove certain individuals from a category based on intolerance.

This is her gender studies woo showing through. She's starting with a narrative and working backwards to shove reality into it, no matter how hard she has to twist it.

If reproduction is the interest, what matters is whether one produces sperm or eggs, whether one has a uterus, a vaginal opening, and so on.

In the end she acknowledges the binary, though she won't outright say it.

To sum up, it's just bluster about the social aspects of sex. If there's something specific you want to talk about that you think is actually stating a viewpoint at odds with actual biologists, quotes would be helpful.