We then examined the ratio of maternal TNF-α to IL-10 in relation to offspring depression, and observed a significant sex difference (χ2 for the sex*TNF-α:IL-10 interaction=13.9; degrees of freedom=4, P=0.008), because of opposing associations of the TNF-α:IL-10 ratio with depression for female versus male offspring (see final column, Table 2). This evidence concerns the gene TNF and major depressive disorder.