Many parents have rushed to embrace Similac Organic infant formula, even though it sells for as much as 30 percent more than regular Similac.

In 2007, its first full year on sale, it captured 36 percent of the organic formula market, with sales of more than $10 million, according to Kalorama Information, a pharmaceutical-industry research firm.

Parents may be buying it because they believe that organic is healthier, but babies may have a reason of their own for preferring Similac Organic: It is significantly sweeter than other formulas. It is the only major brand of organic formula that is sweetened with cane sugar, or sucrose, which is much sweeter than sugars used in other formulas.

No health problems in babies have been associated with Similac Organic. But to pediatricians, there are risks in giving babies cane sugar: Once babies get used to its sweeter taste, they might resist less sweet formulas or solid foods; and some studies suggest that they might overeat.

Carolyn Valek, a spokeswoman for Abbott Nutrition, the division of Abbott Laboratories that makes Similac Organic, said that sucrose had been approved by the Food and Drug Administration and was considered "safe and well established." She said it had no more sweetener than other formulas.

All infant formulas contain added sugars, which babies need to digest the proteins in cow's milk or soy.

NEW YORK TIMES