This is an interesting question. If you mean a competitive FBB I guess it depends upon how much she can tolerate the dieting and training - not talking about the juice here. And, of course, a change in lifestyle: getting married, having kids, going back to their original career, etc., etc.
But there are so many FBBs that I know of on this site, or I have sessioned with, who were competitive, retired from that, and are still FBBs - close to the same physique and look.
