Dec. 7, 2007 -- Got a sweet tooth? It may be carved into your DNA, a newstudy shows.

People have a natural affinity for sugar, but some people like sugar morethan others, note the sweet tooth researchers.

They studied 324 pairs of British female twins. The group included 149 pairsof adult identical twins, who have identical genes, and 175 sets of adultfraternal twins, who share half of their genes.

After an overnight fast, the twins drank sugary water. It wasn't a fancydrink with lots of flavors -- just sucrose (sugar) dissolved in water.

Each twin rated the drink on a scale ranging from "the greatestimaginable dislike" to "the greatest imaginable like."

Identical twins were more likely than fraternal twins to give the drink thesame rating.

Genes explain about half of the variation in how much people enjoyed thedrink, according to the researchers, who included Kaisu Keskitalo, a graduatestudent at Finland's University of Helsinki.

Individual differences explained the rest of the variation. In other words,genes didn't totally explain why some people are especially fond of sugar'staste.

The twins also completed questions about how much they like, crave, and eatsix sweet foods: sweet desserts, sweets, sweet pastry, ice cream, hard candy,and chocolate.

Genes appear to affect those traits, too. But it's not yet clear which genesare involved, or if the findings also apply to men.

The study appears in The American Journal of Clinical Nutrition.