Myths vs facts: FUT2 and fertility

There is a common myth that the FUT2 gene (secretor status) directly determines fertility. The evidence does not support this. FUT2 variants like rs602662 are linked to vitamin B12 absorption – B12 deficiency can indirectly affect fertility by impairing egg maturation or sperm quality. Additionally, secretor status influences gut microbiome composition, which may modulate hormonal and immune pathways. However, the effect is small and not directly causal. Most human studies find no significant association between FUT2 and fertility outcomes such as pregnancy rates or time-to-conception. Consumer DNA tests often overstate such links. The fact is: FUT2 is not a fertility gene. Fertility is multifactorial – age, hormone status, lifestyle, nutrition, and medical conditions play far larger roles. A FUT2 test alone provides no meaningful fertility prediction. Those interested in their fertility should rely on comprehensive clinical assessments, not single gene variants.