Humans exchange millions of disease-spreading bacteria when we kiss. Scientists believe that kissing tests the compatibility of mates ― that it all comes down to swapping spit. But where does the behavior come from?
Fri. Jul 5th, 2024
Humans exchange millions of disease-spreading bacteria when we kiss. Scientists believe that kissing tests the compatibility of mates ― that it all comes down to swapping spit. But where does the behavior come from?