How short is too short for a skirt in an office environment?

[Natalie]

I realize a micro-mini is too short, but a freiend of mine says proper business skirt length is no higher than the knee. It is my first office job. I have lots of cute mid-thigh length skirts that I would like to wear.

 

[Colbert Nation]

If you can see her ovaries ,its too short.