Deloitte publishes its gender pay gap - the story is depressingly familiar

Deloitte has announced that its mean gender pay gap is 18.2% and its mean bonus gap is 50.9%. A depressingly familiar trend is emerging : not only are women paid less but they also receive less in bonuses. In common with so many others who have already published their gender pay gap figures,  Deloitte explains this is due to the lack of females in senior roles. But is that the whole story? Why are bonuses so much higher the more senior you are. Is that fair? Is it because women don't ask so they don't get? It seems to me that we have to look far deeper than retention or recruitment rates if we are ever going to get to the bottom of the issue. What do you think?