BPA became a parent’s worst nightmare in May 2008 when the FDA acknowledged that this chemical—used to make hard plastic—was detected in urine of 93 percent of the population, including infants. A hormone disruptor, BPA migrates from cans and bottles into the substance inside; once ingested, it mimics estrogen and has been blamed for growing public-health problems such as obesity, early onset puberty in girls, reproductive problems in men and breast cancer in women. To go BPA-free as much as possible, reduce your use of plastics and canned food. Don’t microwave food in plastic—transfer it to a dish instead. If you have to use plastic, look for those labeled “BPA-free,” and always let food cool before you store in plastic.