Try listening to the interview again. She distinctly mentions that there is evidence to show gender preference may influence how hormones react. I remind you that I'm not the biological scientist here, so I have to sit up and take notice to what their research has revealed.
Here's what the article actually says:
Van Anders led a recent study looking at the relationship between the "masculine" hormone testosterone and behaviours such as competition and aggression.
She found that the act of engaging in these behaviours was enough to increase testosterone in both men and women — meaning the behaviour was affecting hormones, instead of the other way around.
"So we know that living life as women or men, or as non-binary people, and the gender norms that that involves, can actually influence the ways our hormones act."
She's making one extremely dubious assumption here, and I've bolded it so that even the truly dense can spot it.
If her research indicates that aggressive behavior triggers increased levels of testosterone production, ok. That's plausible.
Where this jumps the shark is the notion that living as a man in our society involves high levels of aggression and competitiveness, while living as a woman is a peaceful tranquil existence free from such mannishness.
Maybe at some points in human history, when a male life meant being a hunter/warrior and a female life meant nurturing children and gathering fruit and seeds, that would be the case. But in our society "the gender norms that involves" don't really differ that much from each other. The idea that a "typical male job" like solving problems at a computer is more aggressive than a "typical female job" like doing invoices at a computer doesn't add up. I'd also suggest that if trans peoples' lives are as stressful and full of confrontation as we're told, it's quite possible that their typical day involves higher-than-average amounts of these "mannish" emotions that apparently cause increases in testosterone production.
-k