MTHFR and Infertility: Other studies from Morocco, South Korea, Brazil, concluded that MTHFR A1298C polymorphism affects male infertility and studies from Iran showed a link between the third polymorphism (G1793-A) and male infertility. Contradictory to this, different studies from Algeria, Poland, France, Italy, and China stipulated no relationship between the three SNPs and infertility in males.