Is modern society restricting our natural instincts to be a good mother?

The rise in women suffering with post natal depression is astounding! My question is, is it any wonder with the world we live in today and the pressure on mothers.
Prehaps the modern idea of 'women can have it all' is affecting us more than we think.
Do women feel they should be doing more because we can rather than because we want to.
Prehaps mothers feel unsatisfied with 'just' being a mother and a homemaker because society is putting constant pressure on women. You can be a mother, a career lady, a lover and a housekeeper.
Women are almost made to feel ashamed these days that they chose to stay at home and raise their children and keep a house. 'What do you mean, you don't work at all, not even part time?' this seems to be a reurcurring question that mothers get asked more and more frequently these days.

The pressure begins at school with the question 'What do you want to be when you grow up?' Now societys dictates that the correct answer to that would be a Dentist, a Doctor a Pyschologist etc, but what if a young girl turns around and answers 'a mother'. She would be considered a right off with no ambition other than to get pregnant and have lots of babies but isn't that what we were put on this earth to do!
These young girls are being pushed into being career driven and going for jobs that produce high levels of testosterone and when women produce to much testosterone they become stressed.

It does make me think that we have it all so wrong and makes me look to people like the Armish who uphold very traditional values. The wife stays at home and looks after the children and keeps the house and the men go out to work.
They are following the natural balance of life. Each person knows their role in life and there is never any pressure on them to do more. Have they got it so right and us so wrong?