Kissing feels instinctive and intimate, yet scientists now argue it is a surprisingly recent and uneven addition to human behavior. Instead of a single romantic origin story, the evidence points to a ...

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. “The meeting of ...

Kissing is a mystery. Science doesn't entirely understand why people do it. Theories abound, but the puzzle remains largely unsolved. Only two other species kiss, chimpanzees and bonobos. But only the ...