We do it as greeting, to show our sexual attraction, or to demonstrate love, but how exactly did the kiss get its start? Scientists have previously argued that the kiss evolved as a way to judge fertility, health, and genes through saliva. However, British scientists from the University of Leeds and the University of Central Lancashire claim, in the journal Medical Hypotheses, that kissing actually developed as a way to spread a necessary germ. The researchers say kissing allows the germ cytomegalovirus to pass from the man to the woman, so she can develop an immunity before becoming pregnant. The germ lives in the saliva and usually doesn’t cause any harm, but if transmitted during pregnancy, cytomegalovirus can kill unborn babies or cause birth defects like deafness and cerebral palsy. Female inoculation is best achieved through mouth-to-mouth contact with a taller man over a period of six months. As the relationship progresses and the kissing becomes more passionate than the first kiss, the woman’s resistance builds. And by the time she becomes pregnant, it’s less likely the baby will be infected by cytomegalovirus. These researchers say the previous reasons given for kissing can be judged by close physical proximity between a man and woman without getting as intimate as a kiss. [The Daily Mail via Impact Lab]
