As a former amat boxer, I can say that boxing/training instills discipline and work ethic, builds character, and all of that good stuff. Messing around at the gym a little might be good for her.

As a former amat boxer I can also say that I would not want any of my loved ones actually fighting.

It's like Rocky said, "boxing is a racket where you're almost guaranteed to end up a bum".

Also, I hate to sound sexist, but I do believe that my 6'3". 225 pound frame is way more capable of taking a beating than any chick. And Clint Eastwood movies aside, I do think brain injuries are more common in women's boxing.