London, April 2 (IANS) Scientists may have the answer to why the opposite sex seems more enticing after a few pegs - they found that alcohol clouded women's judgement.

Researchers at London's Roehampton University asked more than 100 men and women to rate pairs of faces. Some did the tests while drinking a strong vodka and tonic. Others were given a similar-tasting non-alcoholic drink or orange squash.

One of the tests involved looking at faces and stating whether they thought each one was symmetrical or non-symmetrical. Symmetry is known to be tied to attraction, with a face in which one half mirrors the other seen as a sign of good genes and good health, the journal Addiction reports.

The men and women given the vodka and tonic found it more difficult to work out if a face was symmetrical than those on soft drinks, according to the Daily Mail.

Roehampton researcher Lewis Halsey said: People that had drink tended to be less good at noticing if a face was asymmetrical, they often saw it as being symmetrical when it was asymmetrical.

Halsey said: What we have shown is that people's ability to detect symmetry is part of the explanation for the beer goggle effect. The consequences could be considerable.

A lot of people say they met their partner when they were drunk. Are their marriages shorter or longer lasting? Does it change the nature of the relationship?

A Bristol University study found people do appear more attractive to both sexes after they've had a drink - and it takes as little as a pint and a half of beer. In some cases, the mere anticipation of alcohol may be enough to alter judgement.