It can often be a case of IT managers just not trusting their staff to know what they are talking about. Paradoxically, in IT shops where males are in the majority (which IT shop have you seen where this is not the case?) If a female staff memeber pipes up with an idea, it is listened to more readily by Male managers, especially she happens to fit certain physical stereo-types.
O.K call me cynical if you like. Like a lot of issues concerned with IT depts, it is a mixture of Ego and arrogance.