Is FTO useful for fertility?

The provided context does not contain direct evidence linking FTO gene variants to fertility. FTO is primarily associated with obesity in GWAS, and obesity can indirectly affect fertility. However, individual FTO variants have small effect sizes, and fertility genetics is multifactorial. Without specific studies or mechanisms connecting FTO directly to fertility, the utility of such genetic tests for this purpose remains unclear. Consumers should not rely on FTO results for fertility decisions.