Children are the hope for our world—whether they’re our own or simply the next generation. Why else would friends and colleagues tolerate our endless displays of the latest baby—or grandbaby—pics? But since the mid-twentieth century, serious, long-term risks to the fetus and developing child have appeared in the form of toxic and persistent pesticides and heavy metals (often found in sewage sludge that’s used in conventional farming).

Risks to the Fetus

In a process known as “fetal programming,” unborn children whose mothers are exposed to these toxins can experience skewed growth of critical organs and bodily functions later in life, possibly even passing on these altered traits to their own offspring. “Given the ubiquitous exposure to many environmental toxicants, there needs to be renewed efforts to prevent harm,” concludes an international panel of scientists, citing pesticides atrazine, DDT (banned in this country but not others), and vinclozolin as well as heavy metals (like lead and mercury), PCBs (banned but still commonly found in foods), and bisphenol A (from polycarbonate plastics). “A sad aspect with many of these prenatal exposures is that they leave the mother unscathed while causing injury to her fetus,” these scientists add.

“When it comes to toxic chemicals,” explains ecologist Sandra Steingraber, PhD, “the placenta is not really a barrier at all.” Pesticides with low molecular weights cross the placenta—normally one of three places in the human body sensitive to toxins—without restriction.

“Even if the mother’s blood is contaminated with only trace amounts of methylmercury, the placenta will still actively pump it into the fetal capillaries as though it were a precious molecule of calcium or iodine,” Dr. Steingraber adds. “As the pregnancy continues, the mercury levels in umbilical cord blood will eventually surpass their levels in the mother’s blood. In the case of methylmercury, the placenta functions more like a magnifying glass than a barrier.”

Starting 20 years ago, research began linking children’s later higher blood pressure and learning problems with their mothers’ exposures to methylmercury. Today scientists add cancer, diabetes, fertility problems, thyroid disorder, and even obesity to the list of long-term health risks to the fetus from environmental toxins. “Among the effects of toxic exposure in the past have been congenital malformations and other adverse pregnancy outcomes,” researchers also note.

Studies in Iowa and North Carolina show a higher risk for childhood cancers among the offspring of male farm workers who didn’t use chemically resistant gloves. Other research involving prenatal exposure to organophosphate (OP) pesticides shows that just living in a farming community raises fetal risk. Even in urban areas, the offspring of mothers exposed to the pesticide chlorpyrifos are at higher risk for neurodevelopmental damage. The human fetus is particularly sensitive to pesticide exposure since the brain grows and develops very rapidly before birth.

Dangers in Childhood

Because the immune system undergoes critical development after birth (as well as before), environmental toxins may lead to aberrant reactions to foreign proteins (including vaccines), allergies, and increased susceptibility to infections. Plus “pesticides pose special concerns to children because of their high metabolisms and low body weights,” reports the Environmental Working Group (EWG). Sadly, more than one million children between the ages of one and five ingest in excess of a dozen pesticides daily from fruits and vegetables. “It’s children’s aggregate exposure to many different pesticides that causes the trouble,” writ