I remember seeing one in my gym who was in great shape but my training partner said she was probably on something. Just too hard a physique, very hard for a woman to drop down so low in BF (who knows could have been clean).
The dead serious ones probably use or have used something, if you want natural training for years (many may disagree) look at Jodi Miller. No masculine signs at all, good muscle but no where near over the top.