Environmental Pollutants PCBs Change Gender Ratio
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In the 1950s and 1960s, San Francisco bay was heavily polluted with PCBs, a banned group of chemicals once widely used in many industrial products.
PCBs are known to have adverse effects on immune, reproductive, and nervous systems. They cause liver damage, skin problems, and brain damage at high levels. The chemicals are also very persistent, remaining in the body for many years. When waterways are contaminated with PCBs, the chemicals are absorbed by the fish, animals and insects that live in the river or ocean, and if the fish are caught for food, PCBs end up in our bodies, where they can stay for many years.
PCBs were banned in America in the 1970s, as their toxicity was recognized, but they still persist in the environment today, partly due to inadequate disposal of waste products containing PCBs, and partly from contamination and spills, like in San Francisco.
Mothers who were pregnant and exposed to PCBs in San Francisco in the 50s and 60s were much more likely to have female children. Researchers speculate that the PCBs made the loss of a male embryo more likely, or affected the mother’s eggs somehow, so they were less likely to be fertilized by a male sperm.
The moms were 33% less likely to have a boy than a girl. In other words - 67 boys born for every 100 girls.
PCBs are found in significant quantities in breast milk, and most of an infant’s exposure to PCBs comes from breast milk.
As we are told to eat more fish for our health, and breastfeed for our own and our babies health, it’s disheartening to know that both those things increase potential exposure to PCBs.
AS PCBs have been banned for decades, PCBs in the water are decreasing gradually, and for most mothers, breastfeeding is still the most healthy option, unless you know you have been exposed to PCBs or live in a contaminated area.
Fish can still be on the menu too: some fish have much lower levels of pollutants than others. Here’s a list of fish to eat, and fish to avoid.
Source: Medical News Today
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