I would say it would be both of the things you mentioned, anything that would take into account the seasonal and part-time nature of the work many women do, as well as the nature of women's work across their life cycle. Women start out working full time. Often women will stop working full time when they're staying at home to raise their children. Some women choose that option. Some women chose it because they want to spend that time with their children and their families. Some women choose it because of a lack of availability of child care, which is a problem here as well.
Then when women go to re-enter the workforce when their children are in school--it's a common pattern--it becomes very difficult. During that period of time, women lose a lot of the momentum of their careers, plus they have often sunk into poverty, especially single women if they've had to rely on social assistance.