Carriers of the c.677C>T; c.677C>T isoform are routinely referred to a geneticist, on the basis of the additional pleiotropic health risks associated with increased levels of circulating homocysteine,40–43 unrelated to infertility; in particular psychiatric vascular disorders: MTHFR SNPs induce local/hidden methylation imbalances16–18,39–43 including the testis33 and the ovary.44–46 An impact on male germinal tissue in the embryo cannot be excluded, at the time when epigenetic resetting occurs.47,48. Here, MTHFR is linked to Infertility.