Most people shape their lives around having a family - the incentives here are not favourable for females seeking out these sort of positions. Men get a lot more out of being powerful than women - having power is nearly the end of the game for a man. For Tracy it sounds like it was the beginning of a process of disillusionment.
She's obviously robust enough that it didn't really matter to her, but somewhere along the bell curve of personalities that incentive gap will make a difference.