The children's mental and physical growth have been followed since birth. Those children have been compared to a control group of 71 babies whose mothers had not eaten any Lake Michigan fish. The Jacobsons analyzed PCB levels in the blood of the babies' umbilical cords, thus providing a reliable measure of pre-natal exposure. At birth, a mother's overall fish consumption and the PCB level in her baby's blood both correlated with the baby's birth size. At birth, the babies whose mothers had eaten the most PCB-contaminated fish were clearly different from normal children.
Normal babies spend more time looking at the new face.
Babies with more PCBs in their blood, and babies whose mothers had eaten more Lake Michigan fish, spent less time looking at the new faces. Two effects became apparent. Secondly, the remainder of the children were given a series of tests to measure memory and general mental capabilities and, again, the children whose mothers had eaten the most fish had the poorest memories. The balky, uncooperative behavior is of some interest by itself. Significantly, the offspring of those rats showed the same pattern of altered responses to stress, even though the offspring themselves were not fed contaminated fish.