I've never noticed my females having a distinctly dirtier wheel than my males. Two of the hams that peed on their wheels were females, one was a male. The other two didn't pee. Many hams just pee on their wheels, regardless of gender. My robo was notorious for having a nasty wheel. I simply wiped it down with a wet cloth occasionally. So no, I personally do not believe either gender soils their wheel more than the other. Best wishes