In breast cancer, 8% methylation difference was associated with a 1.5 to 3.5 fold expression difference of the ATM gene [34]; and comparing between children conceived in vitro or in vivo, 7% and 9.7% methylation difference in the COPG2 and CEBPA genes related to 2.05 and 1.77 fold changes in gene expression respectively [35]. Here, COPG2 is linked to breast cancer.