Imagine if the Ump' was a nice looking female, there would be whistles, etc. coming
from every direction, that would be very distracting to players and the Umpire.
Also, the ICC could take people whistling, etc. at the female Ump's as sexual
harassment, and that could drive people away from the games because of fear
of being charged. Catching the people whistling and yelling out stuff would be difficult,
if not, near impossible, unless they're spotted doing it by a Police Officier, etc., CCTV
would be useless due to whistling and yelling requiring very little body movement.
Another thing. What if a female Ump' is pregnant and told she can no longer
Umpire any more matches until she's given birth. She could start a lawsuit
against the ICC for discrimination. This sort of thing has happened before in sport,
even when it was at the benefit of the pregnent woman and her unborn child.
I don't think there would ever be female Ump's in International Cricket,
robots would be doing the job long before they get a chance to.