Santhi Soundarajan (1) shows exactly how this ends up catching cis women who were raised as women from birth. Which is why it's a bad idea to draw strict lines.

Edited to add: Based on http://linuxmafia.com/faq/Essays/marriage.html I just discovered another case, that of Polish sprinter Ewa Kłobukowska who was banned from sports in 1967 and stripped of her medals for failing a sex test even though she gave birth to a child a year later. For the 1996 games 8 women failed their sex tests, but 7 of them had AIS and one had 5-alpha-steroid reductase deficiency. All of them were reinstated, and that's when the Olympics ended their previous iteration of genetic testing female athletes.

This idea has a long history, and it's a long history of being wrong. I'm not expecting any better out of it this time.

1: https://en.wikipedia.org/wiki/Santhi_Soundarajan The first female Tamil athlete to win a medal at the Asia games (in 2006), then had her silver medal stripped from her because she had Androgen Insensitivity Syndrome- so she's a XY who never developed male genitals because her body just ignored the chemical signals, as happens to something like 1 in every 40,000 births. She tried to commit suicide by drinking rat poison after she came home in disgrace.

http://linuxmafia.com/faq/Essays/marriage.html discusses some of the genetic anomalies that are possible and coincidentally how they've been handled by the IOC.