Maternal preconception diet and the sex ratio

Temporal variations in the sex ratio or the ratio of boys over girls at birth have been widely studied and variously attributed to social changes, conditions of war, and environmental changes. Recently, Mathews, Johnson and Neil (2008) studied the direct evidence of individual pregnancies and established an association between the sex at birth and the mother’s preconception diet. We examined the hypothesis using new evidence from the wartime famine in Holland in 1944/45 and failed to show an association between maternal diet in pregnancy and the sex ratio. This makes a causal link highly improbable.