Consumer reports has released an analysis of FDA tests on the dangerous mercury levels in canned tuna and other fish, advising pregnant women not to consume any quantity. The reason behind the warnings is that fetuses, as well as young children-- whose brains, hearts and nervous systems are still developing-- face the most risk of impairment.

Studies of fish-consuming communities have linked mercury exposure in babies and small children to subtle neurological and behavioral impairments. Later in life, those mercury-exposed also experience cardiovascular and immune system deficiencies. These deficiencies could have roots starting in pregnancy.

The consumer report mainly focuses on the dangers for pregnant women, however it also advises women of child-bearing age to limit exposure as well. The reason is that mercury can linger in the body even after you've stopped eating fish. The report features a guideline for safe fish consumption for everyone from small children to the elderly.