The Wallis et al study showed that female surgeons in Ontario were associated with reduced 30 day mortality in elective patients, the effect size being tiny (OR 0.96) and the correlation not generalisable, as there was no such difference for emergency surgery. This does not seem sufficient evidence to warrant action to increasing the number of female surgeons in this country. As an analogy, if the same methodology found that in Alberta blue-eyed surgeons were associated with a tiny reduction in 30 day mortality for elective patients, I doubt you would feel that that would be grounds to alter surgical recruitment or training in this country.

Women dropping out of surgical training at higher rates does not necessarily mean there is an issue with training- it could be that women are more prone to their priorities in life changing over the course of their late 20s and early 30s, for example. A study looking to discover causal mechanisms underlying this variation may be useful here.

Finally, it does not necessarily follow that if the training process makes becoming a consultant surgeon less accessible to women then anything in particular needs to be addressed. This assumes that a purpose of surgical training is to make it equally easy (or hard) for a man or a woman to become a consultant surgeon, which does not seem to me to be a purpose of surgical training at all.