Admit it. You've wasted an afternoon or two on HotOrNot.com, doling out nines to anyone who flashes a little skin and twos to people with glasses.

To determine what really counts on the website, Pierre Tourigny made composite images of 15 women grouped by rating. Each image melds the faces of about 30 women into one.

The thinner and more symmetric faces turned out be "hotter" - hardly a surprise.

Dozens of other studies have confirmed that both men and women prefer mates with symmetric faces, perhaps because they are an indicator of development genes with few harmful mutations.

The low-rated composite faces tended to be fatter and, to my eyes, less symmetric. But overall, Tourigny notes that the composite faces proved hotter than the sum of their parts - probably because the morphing process smoothed out zits, scars and other blemishes.

He did the same for women in four age groups - all over 18, thankfully - as well as for Miss Universe contestants.

Think you and your mates are better than the sum of your faces? Make your own facial composite here.

Ewen Callaway, online reporter