For generations, the hope that a mother's diet might shield her child from allergy has carried an intuitive appeal — the idea that tolerance could be seeded before birth, through the quiet chemistry of amniotic fluid and breast milk. A large Australian trial enrolling over two thousand pregnant women has now tested that hope directly, finding that substantially increasing maternal egg and peanut consumption during pregnancy and breastfeeding produced no meaningful reduction in food allergy among high-risk infants at one year of age. The findings do not diminish the importance of what mothers e