There's something fundamentally different about women that enables them to give birth to children. Humanity has been discussing the differences in behaviour between these two groups for literally millennia. Are we really going to just decide by fiat that there is zero possibility of a difference in inclination or ability that lends itself to women simply not wanting to be in this field as much as men?
You essentially have to practice some kind of biological denialism in order to believe this "problem" is entirely managerial in nature. Discussing biological differences between sexes should not be considered sexism.