Its not really fair to adjust for factors such as not taking time off to have kids. There are a number of biological reasons why it makes sense for women to be

Its not really fair to adjust for factors such as not taking time off to have kids. There are a number of biological reasons why it makes sense for women to be more involved in the early stages of rearing children than men (for example - only women can breastfeed). For career focused women it is a very big problem that many career paths don't allow an easy way to take time off (or even just slow down a little bit) for children and then come back to reasonable opportunities.