MTHFR and Infertility: Furthermore, a similar results were reported in a study of individuals with or without oligozoospermic which showed no significant association between DNA methylation in spermatozoa and the MTHFR C677T genotypes although a trend for higher incidence of methylation alterations in severe oligozoospermic infertile men with CT genotypes were observed34, suggesting that a much more complicated or indirect interactions between MTHFR polymorphism and methylation are involved.