(FORTUNE Magazine) – Sexual harassment. Wage disparities. The glass ceiling. It's not as if women need another hurdle to deal with in the workplace. But here comes one anyway: A recent survey suggests that women executives are being held back because they aren't very funny. The 359 managers polled, all alumni of the Perdue School of Business at Salisbury State University in Maryland, gave a far higher overall effectiveness rating to both male and female supervisors who use humor (either joking around themselves or laughing when others do) than to those who don't.

But far fewer women bosses ranked high on using humor effectively around the office. "Many women may feel that using humor isn't appropriate for them, so they stifle their sense of humor in the business world," says Wayne H. Decker, the Perdue management professor who conducted the poll.

He's not advocating stand-up comedy at the water cooler but says, "Humor can be useful in expressing ideas, making light of a situation, assigning tasks, easing tensions, or even communicating work-related information."

Okay, here goes: So this guy walks into a bar with a pig under each arm and a duck on his head...

--Anne Fisher