Everyone loves to pucker up – especially singles when they exchange their first all-important kiss – but kissing is particularly fascinating to scientists. They've even given the study of that lip-locking subject a name, "philematology", but we think "kissology" is sexier, so that's what we'll call it.

Depending on where the kissologist is coming from – which branch of science was their primary base – theories differ on why we kiss. And not all cultures do kiss, with something like 10 percent of the world living in a lip-lock free zone, as observed by Helen Fisher, an anthropologist a decade ago.

One thing kissologists seem to agree on is that when we kiss, that's when the chemistry happens – or doesn't happen as the case (or perhaps kiss) may be. There's no such thing as a good kisser or a bad one, it's just how well we connect chemically with the person on the other end of our lips. Respected publication Scientific American tells us that's there's a whole bunch of chemical reactions taking place when we kiss, and this chemistry tells us how genetically compatible we are. Other kissologists say the enjoyment level of the kiss is an indicator on how compatible you and your potential partner will be when the lights are turned low.

Good kissers don't grow on trees according to a recent Australian women's magazine survey, with 71% of women indicating their first kisses where usually out of sink and felt un-coordinated. Over 40% of single women in America are using free American dating websites to build chemistry with potential match's before going in for the big pash with a virtual stranger after being plied with white wine at the local bar.

But as we venture out of the singles online chat rooms into lip-land, we find that smooching means something different to American women as it does to American men. More than 1000 students taking part in a State University of New York study revealed that kissing was far more important to women than to men. For men, kissing was used "to increase the likelihood of sex," said a report in Evolutionary Psychology. But for women, it was a way of sizing up a partner, and then to "check" how the relationship is going later down the line.

Dr Glenn Wilson from London's Institute of Psychiatry specializes in relationships, gets down to the nitty gritty – the facts of life answer to the question of kissing: "Kissing is used by everyone as a bonding and testing mechanism.

"But the fact is women are more discriminatory than men. Men can just go out and spread their seed, but women have to take more responsibility because of the consequences and so they are likely to want to test more."

The State University's Dr Gordon Gallop puts it another way: 'We see kissing as an evolved courtship ritual. At the moment of a kiss there's a complicated exchange of information…"

There is, obviously, some serious biological stuff going on behind the kiss – the most intimate act between two people.