Peter Attia, M.D.

And phenotypically, a woman with Turner's syndrome does appear phenotypically female.

Yes.

But I believe she's not able to reproduce?

But she's sterile under maybe natural conditions.

But her stature is distinctive.

And there's a sort of... Wider neck and a few other characteristics.

And so something about these 20% or thereabouts of genes on the supposedly silenced X chromosome are clearly making the difference because that would be the biggest difference you would notice.

And is it always the same genes?

At about what stage of development?

How many months or weeks?

The point is, somewhere in the early second trimester...

That level of testosterone in a male fetus is comparable to what... It's lower.

If a male in puberty is at 1,200 nanograms per deciliter, this could be 600 nanograms per deciliter.

But still screaming high.

I didn't know that.

I missed that memo, fortunately.

And just to make sure people are following this logic, there's one part of the swing we didn't finish.

And it's because I keep interrupting you, so it's my fault.

But I'm going to do my best to synthesize this.

Testosterone, you have this real peak difference in testosterone during a critical window of development when the brain is developing.