For the first time, researchers have shown that poorly controlled maternal diabetes has an adverse effect on methylation of the maternal imprinting gene Peg3, contributing to impaired development in offspring. Previous studies have revealed that offspring of diabetic mothers display a higher incidence of malformations and fetal death, even when a one-cell embryo is transplanted from a diabetic to a non-diabetic mother. Diabetic mothers’ oocytes tend to exhibit reduced glucose metabolism, compromised communication between cumulus cells and oocytes, mitochondrial malfunction, and a decreased ovulation rate, all of which can be traced back to reduced gene expression in the embryos.