Even by the age of 2 weeks, babies are more alert and exploratory if they have a "novelty-seeking" gene that may influence sensation-seeking in adults, researchers reported Sunday.

Babies with the gene DRD4 were more likely to follow a red ball with their eyes, respond to a human face and pay attention to the sound of a rattle than other babies, according to an Israeli study of 81 infants just two weeks after birth."Some of the reason they do that is because of a particular form of a gene," said lead researcher Richard P. Ebstein, a molecular geneticist and laboratory director at the Sarah Herzog Memorial Hospital in Jerusalem.

The newborns' response to their surroundings "seems to be based on the same genetic (variation) as an adult," Ebstein said. "A child who even at two weeks reacts strongly to stimuli, seems to be alert, doesn't get scared, doesn't freeze in the crib - that same person at 20 years old is willing to go mountain climbing, biking and drive his car too fast."

Outside observer was skeptical of the study even though he said the theory was plausible.

"The sample sizes are much too small to be confident of these results," said James Swanson, a pediatrics professor who heads the Child Development Center at the University of California, Irvine, where he specializes in attention deficit hyperactivity disorder.

The novelty-seeking gene is controversial because some studies have failed to find a link to personality while others have indicated connections to addiction and hyperactivity.