Kissing, for all popularity, is a bit of a mystery. Scientists have long debated when humans’ ancestors first put their lips together, and whether the act is simply a cultural trait. A new study ...

A Babylonian clay model dated to 1800 B.C.E. shows a nude couple on a couch engaged in sex and kissing. The Trustees of the British Museum “My upper lip becomes moist, while my lower lip trembles! I ...