By Lisa Rapaport Fathers are conspicuously absent from studies that test the best ways to prevent and treat obesity in children, according to an analysis of research done in the past decade. Investigators focused on randomized controlled trials designed to test whether a specific intervention can directly prevent obesity or help children who are already obese lose weight. Fathers accounted for just 6 percent of participants when only one parent was allowed to join studies of pediatric obesity, the researchers report in Pediatrics, online January 27.