Is HLA-DQ2 useful for fertility?

HLA-DQ2 is not a direct fertility marker. The link is indirect via celiac disease: untreated celiac can impair fertility due to malabsorption and inflammation. HLA-DQ2 is the main genetic risk factor for celiac (≈90 % of patients carry it), but only 3–5 % of genetically susceptible individuals develop the disease. A positive result does not mean fertility is affected. Evidence is mechanistic (celiac → fertility) and not strong for HLA-DQ2 alone. Caveat: Do not change diet without medical guidance. A celiac antibody test (tTG-IgA) is more informative than a standalone DNA test.