Depends within which role, if you talk about retail then this may mainly be because females could know more about fashion as-well as they are hired to attract more customers in (the nasty truth). How ever I believe this thought has changed there is an equal amount of both genders working within retail. If you talk about law, you may notice more males working within this industry as more males are graduated within this role... same goes to social workers there are more females because there is more females that have graduated within this role...
Hope this makes sense :)