There is no such thing.
I started with AA 2102. Some loved it, some said it was sized for children.
The short of it is that shirt size names (Large, Small, etc) have NO defined meaning for women's shirts across brands or even within brands on different styles. (The size names derive from men's jacket sizes, and are pretty standard across men's T-shirts from small to 1X in terms of chest measurement, overall cut still depends on whether it is a Boxy or a Fitted cut.)
I use the NL 3900 for a slim fitting women's shirt and the Bella 6400 for a relax fitting shirt. I have no returns for size since I gave them those options (and made it very extremely freaking clear which was which and what was what--I put my description of the style (Relax/Slim and the bust size and women's dress size # in the size selector ahead of the size name, as the size name is the least important and most misleading piece of info about the shirt)).
I almost quit offering women's Ts before I finally came to a solution that works.
Also, some women will prefer to buy a boxy men's style. The spectrum of waist and a bust variation, as well as personal fitment preference, makes a "One Style Fits All Women" goal impossible to meet.
