Contrariwise, no correlation was found between methylation errors at H19 and MEST genes and inactivating MTHFR C677T single-nucleotide polymorphism (SNP) [a cytosine (C) to a thymine (T) substitution at position 677] in sperm DNA from infertile patients with defective semen parameters. This evidence concerns the gene MTHFR and Infertility.