Scientists say they’ve found an infection more likely to strike women than men: the yawn. Many of us have felt that irresistible urge to yawn after seeing a colleague or buddy yawn. Though the reasons ...

Here's a challenge: Try to read this whole page without yawning. Even reading the word yawn might be enough to set you off. But why do we yawn in the first place? And why do we 'catch' other peoples'?