Scientists from New York State University have found that men and women view kisses differently, with females more likely to judge a potential mate on the first kiss.
Finding subtle differences in kissing techniques is an evolutionary trait developed by women to find the perfect match for children, the experts said.
As well as being a turn-off, bad breath can be a sign of health problems and a negative memory of a first kiss for potential mothers.
Lead researcher Dr Gordon Gallup explained to the Daily Mail: "While many forces lead two people to connect romantically, the kiss - particularly the first one - can be a deal-breaker.
"Kissing is part of an evolved courtship ritual. This may activate mechanisms that function to discourage reproduction among individuals who are genetically incompatible."
The study also found that women see kissing as an important bonding mechanism which is important to the long-term maintenance of a relationship, while men see kissing as less important later on in a courtship.
