Can FTO help with fertility?

Whether the FTO gene (e.g., rs9939609) can help with fertility is not clearly established. FTO is primarily known for its association with obesity and BMI. Obesity can impair fertility in both women (hormonal imbalances) and men (reduced sperm quality). Some studies suggest a weak, indirect effect mediated through BMI, but direct, independent links between FTO variants and fertility outcomes are not robustly replicated in human research. The effect size is small, and lifestyle, diet, and hormonal status play much larger roles. A DNA test for FTO alone does not provide meaningful fertility information. For individual assessment, comprehensive testing (hormone panel, semen analysis, etc.) is needed. Evidence: based on population genetic associations (GWAS) and mechanistic reasoning, not on clinical fertility trials.