2. For obese subjects, body mass index for age above the 85th percentile (determined by NHANES I age-, sex-, and race-special data). For normal weight subjects of obese parents, body mass index (determined by NHANES I age-, sex-, and race- specific data) between the 5th and 85th percentile and both parents' current body mass index above 25 kg/m(2), or a history of a body mass index above 25 kg/m(2).