@Lee once upon a time, a wizard created watches on the wrist for the ladies, then evil pilots said "hey! we need those too!" So the wizard's friends started making these watches for pilots, and men, because more men were pilots then. And now, it became a man's thing... at least according to IWC.
The version of the story I heard is that prior to WWI, wristwatches were considered a feminine accessory. Men carried pocketwatches, but those were unwieldy, so american doughboys adopted wristwatches for field use.