How are FUT2 and fertility related?

The relationship between FUT2 (fucosyltransferase 2) and fertility is an area of ongoing research, but the evidence is not yet strong enough for clinical guidance. FUT2 determines secretor status: individuals with a functional FUT2 gene (secretors) express certain blood group antigens in body fluids, while non-secretors do not. Some studies suggest non-secretor status may be associated with a higher risk of urinary tract infections, bacterial vaginosis, or altered cervical mucus composition, which could potentially affect conception. Other research links FUT2 variants to differences in gut microbiota composition, which might indirectly influence fertility. However, effect sizes are small, studies are heterogeneous, and findings are not consistently replicated. A genetic test for FUT2 cannot reliably predict individual fertility. Lifestyle, age, hormonal health, and other factors are far more important. The evidence is best described as mechanistic/mixed – plausible biological links exist, but robust human data are lacking.