Women's workstations tend to harbour far more germs than those of their male colleagues, research suggests.
Keyboards can harbour germs
A University of Arizona team found the average office desktop harbours 400 times more bacteria than the average office toilet seat.
However, they also found that on average women have three to four times the amount of germs in, on and around their work area.
But men's wallets provided the most fertile bug breeding ground of all.
The researchers said women's habit of keeping snacks in their drawers could explain why their desks were more germ-ridden.
They also warned that make-up and lotions helped to transfer bacteria.
Lead researcher Professor Charles Gerba found that 75% of female employees kept food in their work area.
He said: "I thought for sure men would be 'germier'.
"But women have more interactions with small children and keep food in their desks. The other problem is make-up.
"I was really surprised how much food there was in a woman's desk.
"If there's ever a famine, that's the first place I'll look for food."
Professor Gerba added that men's wallets provided a very attractive breeding ground for bugs.
He said: "It's in your back pocket where it's nice and warm, it's a great incubator for bacteria."
Don't take risks
Professor Sally Bloomfield, chairman of the International Scientific Forum on Home Hygiene, said people should not be unduly worried by the findings, as most bacteria did not cause disease.
She said: "It is not whether bacteria are present, or how many there are, but what type they are.
"But if you leave food on your desktop that you would usually put in the fridge at home, then you are asking for trouble."
The Arizona team took samples from 100 offices at the university and in New York, Los Angeles, San Francisco, Oregon and Washington.
They swabbed eight sites in each office: the phone, desktop, computer mouse, computer keyboard, exclamation key on the computer keyboard, pen, bottom of desk drawer, and handle of desk drawer.
They also took samples from workers' personal items.
The mouldiest spot was the bottom of the desk drawer, where many people stash food.
The study was commissioned by disinfectant maker Clorox.