As compared to the fetal response, neither IFNβ (Fig 3V), IL‐1β (Fig 3W), IL‐1α (Fig 3Y), nor GM‐CSF (Fig 3C′) showed a significant response to infection in maternal serum, suggesting that these cytokines are unique to the fetal hematopoietic response to maternal infection. The gene discussed is IL1B; the disease is infection.