If, as stated, the IT workforce is largely male, then the management of those departments is necessarily going to largely male. You aren't going to do much to change the ratio unless more women enter IT from the bottom. Where are all of these extra IT managers supposed to come from? HR? That there aren't more women in IT and management isn't the fault or responsibility of the corporate IT departments. The problem has to do with why there aren't more women in IT and that goes back to societal norms and expectations. If the structure of society is to blame, then that is certainly not a problem that IT can or should be expected to fix. They need to find the right person for the job and, while there is probably discrimination, I think the problem is mostly because there just are enough female candidates out there in the first place.