You are at a table for two, sitting with your girlfriend or boyfriend, when, for no good reason (you can't help it, you didn't mean to do it), you yawn. It's a big, gaping, jaw-extending ...

Humans’ first experience with yawning happens in utero, says Matthew D. Epstein, M.D., associate medical director of the Atlantic Health Sleep Centers in New Jersey. Yet, Earth-side, the ...