“The whole issue of sipping came as a surprise,” said Dr. Monika Wadolowski, an epidemiologist who is a postdoctoral research fellow at the University of New South Wales Australia and the lead author on the study, which looked at 1,729 Australian seventh graders. She was drawn to the topic, she said, because some statistics were identifying high rates of early alcohol use in adolescents, but they weren’t distinguishing between the kids who had “sipped” and the kids who had had whole drinks.