Copied and pasted from another thread:
Partly it's about inflexibility. Partly it's about the long hours culture. But, in my experience at least (though I'm not particularly senior) it's about the culture of the work environment before you are even pregnant.
My decision to quit the job I had before I was pregnant (I hung on for a while after coming back from maternity leave) had as much to do with the drip drip of insidious sexism and the acknowledgement that women, even though lip service was paid to equality, were never going to be promoted. It's not the big things, it's the little things. Like:
The kitchen/tea room being seen as the responsibility of the female staff to keep clean. I never saw a man empty the dishwasher for example.
Sexist 'jokes' that went unchallenged or were expected to be treated as 'banter'. e.g. the inevitable comment about liking to see a woman on her knees every time I climbed under desks to fiddle with some cables. Not to mention the 'hormone' joke or rolled eyes if a woman gets angry.
The favoritism given to men. I don't know why they don't realise that we notice when male colleagues are given more training opportunities, promoted quicker and leave work early without comment. And let's not forget the number of times my suggestions were noted only after they came out of a man's mouth or the assumption that the woman in a meeting always takes the notes.
The different dress codes. I'm in the upper echelons of middle management. In meetings, especially amongst us techie types, the difference between what is acceptable for a man and what is acceptable for a woman is glaring. The men can get away with neat jeans an T shirts but that if frowned upon in the women. Without exception the women are expected to be groomed in a way men aren't.
The belief that presence = commitment. I leave at 5pm on the dot every day. This is not because I lack commitment but because I am efficient. I don't spend my time farting about on facebook and playing games in time wasting tasks. (she says's posting from work, though in my defense, I'm on my phone waiting for a person to turn up for a meeting). Like many of my female colleagues I'm in work reasonably early and, by the time many of my male colleagues appear, have put in some seriously efficient quiet work time where much gets done. But inevitably, the early starts aren't noticed but the prompt leaving is.
I guess, like many women I took time during maternity leave to take stock. I saw an environment where young, poorly qualified and inexperienced men were promoted over efficient capable women. I saw these women having to manage their bosses and tidy up after their mistakes. I saw the glass ceiling. I wondered if I really wanted to work for a company that clearly didn't value me or my gender but were prepared to exploit us none the less. I could see any woman who had been promoted forced to conform to the company culture and laugh along with the jokes while keeping the women down. So I thought, like so many others, it's simply not worth it. I went somewhere else.