Really? You need me to explain this to you?
OK, if there is no bias then everyone has an equal chance of progression - depending purely on their individual talents and qualities. If there is a skew towards one demographic as you rise through the ranks, that either shows that that demographic is inherently better suited to more senior roles or there is a bias.
If you don't believe there is a bias, what is it about men that makes them more suited to being CEOs? Or bankers? Or sewage workers?
I will never adhere to any quotas. I own my own company I have always and will always employ the best person for the job.