Just as frogs’ mating season arrives, a study by a Yale professor raises a troubling issue. How many frogs will be clear on their role in the annual springtime ritual? Common frogs that make their homes in suburban areas are more likely than their rural counterparts to develop the reproductive abnormalities previously found in fish in the Potomac and Mississippi Rivers, according to the study by David Skelly, a professor of ecology at the Yale School of Forestry and Environmental Studies. Dr. Skelly’s research found that 21 percent of male green frogs, Rana clamitans, taken from suburban Connecticut ponds are...