More than half of U.S. adults surveyed by Harris Interactive have used their mobile phones in the restroom, and about one in five adults ages 18 to 24 admit to dropping a phone in the toilet in the process.

And Microsoft found it necessary to commission the study to find those things out.

The company released the results today in conjunction with Windows Phone 7's debut in the U.S. -- using the survey to make the case that the country is plagued by "Bad Mobile Phone Behavoir," and that its new mobile operating system is in a position to help, with a user interface designed for quicker information access.

The study dovetails with a previously released Windows Phone commercial in which a man drops a phone in a urinal.

Other critical factoids from the study: Half of people ages 18 to 24 have tripped or walked into something while texting or emailing on their phones. And 69 percent of adults 18 to 34 have used their mobile phones in bed.

See this earlier post for our more serious coverage of the Windows Phone 7 launch, and our first impressions of one Windows Phone device.