Pursue a policy that every employee, especially women, from their first day at work are aware that every position in the organization is equaly available for men and women. Hold meetings to raise awareness, make the information clear to the employee at their firts day briefing. So every woman can be confident, that if she works hard and have required skills, top positions in company will be open to her. Also male employees will be more ready to work, having a woman boss and start to feel that it is a normal situation.