I know several women who run saw professionally. They are just fine. They generally run 60cc saws. There is no reason why a female can't run a chainsaw well. The question is: does your wife run other tools like drills, circular saw, grinder,mitre saw, etc? A chainsaw is NOT the first powertool someone should run, IMO.
There is also a certain amount of strength required. Any farm girl I know is certainly strong enough.
I would not let a newbie run a saw without a brake or PPE, just because.
JFTR, EVERY well experienced saw hand I know HAS had a reportable accident at some point in their career and many close calls over the years. It is a dangerous occupation. In fact, in BC, Canada it was known that there are more deaths/capita in the forestry industry than all others combined. That was known in about '95 and it may have changed by now. I hope so, with all the training that goes on these days.
PS., the first time I went big-game hunting with my Dad, before I could have a licence and before I had ever shot a centre-fire rifle, he fired a shot across a little ravine into the dirt just as it got dark. The flame shooting out of the barrel left a lasting impression on me. It was then and there I realized I had to pay attention with a firearm.
Maybe the chainsaw lession could be to cut a big piece of frozen meat, including the bone.....or something. Or not. LOL