I'm a woman doctor, training in hospital medicine. Agree that consultant hiring decisions are very nearly gender-blind, and the NHS appears very benign towards us as women compared to many other employers. A few months' maternity leave, when you are young and still learning the ropes anyway, is small beer compared to 25 years of hard graft working for a NHS Trust. (The maternity leave issue can be a bigger problem for female GP partners, but that's another story).
Yes, the specialities with anti social hours (often more prestigious too) are still rather male dominated with often very macho, inflexible cultures, and women tend to vote with their feet as theDudesmummy implies. But many other specialities, often with less acute/out of hours work (but not always - eg paeds), are now actually female-dominated at consultant level. In my own happy, friendly speciality it's probably about 50:50, which is nice.
It's not all about hiring decisions, of course: there are many other, more subtle issues affecting woman consultants that can make their lives harder, but most of those relate to society as a whole, not a problem of the NHS as such.
Mind you, you have to remember the consultants do not hold the power in the NHS, not really. Consultants just deliver the service. That word says it all: towards patients, we really do consider ourselves servants; it is hard for us to imagine actually setting out to oppress the people we are trying to help.
Amongst ourselves doctors can be intensely competitive. Any consultant who really wants to go on a power-trip will be seeking out the real positions of power and influence. These positions - eg senior Trust positions, royal college positions, research professorships, deans of medical schools, learned society presidencies, writers of reports for the Govt and influencers of policy at national level - are still very much the domain of the "old white men".