What to watch with FUT2 and fertility?

The FUT2 gene encodes a fucosyltransferase that determines secretor status – whether ABO blood group antigens are secreted into bodily fluids like saliva, mucus, and vaginal secretions. Non-secretors (inactive FUT2 variants) have an altered vaginal microbiome, typically with fewer protective Lactobacillus species and a higher risk of bacterial vaginosis (BV). Since BV is linked to preterm birth, pelvic inflammation, and impaired implantation, FUT2 status may indirectly affect fertility. Some observational studies suggest lower conception rates in non-secretors, but the evidence is moderate and not yet clinically actionable. Causal links are unproven, effect sizes are small, and confounding factors (e.g., diet, hygiene, sexual practices) are often uncontrolled. A FUT2 genetic test can provide background information, but it should not replace standard fertility workup (hormones, cycle tracking, infection screening). Currently, there is no validated intervention based on FUT2 status to improve fertility. Consumers should be cautious about overinterpreting such results and focus on well-established modifiable factors.