How are FUT2 and Fruchtbarkeit related?

The relationship between FUT2 and fertility is indirect, mediated through vitamin B12 metabolism and the gut microbiome. The FUT2 gene determines secretor status: secretors (G allele) secrete fucosylated oligosaccharides into body fluids, influencing gut microbiota composition. Non-secretors (A allele) tend to have lower vitamin B12 levels due to reduced absorption. Vitamin B12 deficiency is linked to fertility issues such as prolonged time-to-pregnancy and increased miscarriage risk. However, the effect is modest and modifiable by diet, gut health, and other factors. A DNA test alone is not a fertility test. Evidence comes from GWAS and observational studies, not clinical trials. Therefore, it is informative but not clinically actionable. Anyone with fertility concerns should consult a doctor for comprehensive evaluation.