In analysis by breast cancer intrinsic subtype, weight gain from ages 18–24 onwards was inversely associated with Luminal A‐like (ER+ PR+ HER2−) breast cancer and weight gain from ages 18–24 to 35–44 and to 45–54 years additionally with luminal B‐like (other ER+/PR+) breast cancer risk (Supporting Information Fig. S4). The gene discussed is ERBB2; the disease is breast cancer.