Nature's most perfect food, breast milk, helps growing infants develop resilient immune systems. But along with the welcome antibodies are the persistent toxins she may have ingested in her lifetime which are stored in mother's fatty tissue and are also passed on to baby. As mother of a newborn, reporter Andrea DeLeon grappled with the dilemma of balancing the health risks against the benefits of breastfeeding her son Carter, and shares her findings with us. We are re-broadcasting this feature as it recently won the AAAS (American Association for the Advancement of Science) Science Journalism Radio prize.