If it isn't necessary, then why do so many women do it??
It so happens that many women do feel it's very important to be at home in their children's early years. Some don't, but many do, and it has always been that way. Why, why is it always women who have to change their intrinsic values, change their priorities to fit into what many would argue is a mans world? We already sacrifice so much to have children, including income, but that doesn't mean women should miss out simply because they rate being available to their babies in those early years higher than going back to work to earn as many $$ as they can.
The way the system currently is suits men to a tee, but not women. We need to change this.