In this season of sugar plums, scientists at the Monell Chemical Senses Center have studied the science behind a phenomenon familiar to many parents: Some children have a much keener sweet tooth than others.

In a study in the journal Nursing Research, scientists at the Philadelphia research institution found some kids could detect just a few thousandths of a teaspoon of sugar dissolved in a cup of water. Other children in the study needed more than 20 times that much sugar before they could detect it. One needed a whopping three teaspoons in the water to be able to perceive it.

Oddly, the children who were more sensitive to sugar reported that they ate more sweets. They also were generally heavier, and their tongues were more likely to have receptor proteins especially sensitive to bitter tastes.

Monell behavioral geneticist Danielle Reed, one of the authors, said more work needs to be done to determine what the results mean.

Bottom line, the evidence suggests a person who craves sweets is simply wired that way.

"I think people often feel that it's cultural, or it's personality," Reed said. "It's inborn biology. It's like people are born color-blind."

- Tom Avril