Greater gestational hyperglycaemia amongst South Asian women [11–14] is a plausible exposure that could contribute to greater fat mass at birth in South Asian infants because (1) greater circulating pregnancy fasting and postload glucose concentrations promote fetal insulin secretion and fat accretion in a linear dose–response fashion [15–19]; and (2) an increased risk of gestational diabetes mellitus (GDM), hyperglycaemia and type 2 diabetes in people of South Asian origin is well established [1, 11–14, 20–25]. The gene discussed is INS; the disease is type 2 diabetes mellitus.