The relative risks of potentially toxic compounds found in seafood compared to the potentially beneficial nutrients rich in seafood is a significant public health issue and has been the subject of an US Federal Advisory in 2004, which limits seafood in pregnancy. A major impetus for conducting this research is the finding from the ALSPAC cohort that compliance with this advisory appears to be associated with greater risks of the specific harms (e.g. suboptimal verbal development) it was designed to prevent. This prior analysis, conducted as a collaboration between LMBB/NIAAA/ NIH and ALSPAC, compared dietary intakes during pregnancy estimated by food frequency questionnaire data, to childhood developmental outcome data. The findings of lower than expected verbal IQ and other suboptimal outcomes such as poor fine motor development and adverse socialization among the cohort, do not appear to be attributable to confounding variables. This increased risk of suboptimal developmental outcomes may be due to deficiencies in nutrients uniquely rich in seafood, potentially the long chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acids (DHA). Several lines of evidence indicate that insufficient dietary intakes of EPA and DHA increase the risk of neurodevelopmental impairments. Among these are that DHA is selectively concentrated into neuronal tissues and the proliferation of neuronal dendrites and synapses is substantially enhanced by DHA. Since the main source of DHA-EPA for humans comes from the dietary intake of fish & seafood (or fish oil dietary supplements) the evaluation of food frequency data from the ALSPAC cohort indicates that pregnant women need a sufficient intake of DHA-EPA in order to prevent increasing risk of suboptimal outcomes among their offspring. Another nutrient uniquely rich in seafood, selenium has a protective effect against mercury in utero in animal experiments. As selenium is fairly high in most marine fish/seafood, there could be a natural offsetting of the dietary ingestion of methylmercury present in marine fish/seafood versus the selenium present in the marine fish/seafood. Selenium is thought to bind with and detoxify methyl-mercury and a greater ratio of methyl-mercury to selenium is thought to indicate that the primary protective mechanism against methyl-mercury toxicity has been overwhelmed. However, the impact of this relationship in humans needs to be evaluated as previous research on mercury or methylmercury may be inherently flawed as selenium was not simultaneously considered with the mercury.