How are CYP2C19 and fertility related?

The provided context does not directly link CYP2C19 to fertility. CYP2C19 is a drug-metabolizing enzyme that breaks down clomiphene, a medication used for ovulation induction in infertility treatment. Genetic variants (e.g., CYP2C19*2, rs7579) can reduce enzyme activity and potentially alter clomiphene efficacy. However, the evidence is moderate: human studies exist but lack large randomized controlled trials directly linking CYP2C19 variants to fertility outcomes. The allele frequencies shown in the context (e.g., T‑allele ~24–36 %) come from population databases, not fertility studies. Thus, the clinical utility for individual fertility advice is limited. A CYP2C19 test may offer guidance during clomiphene therapy but does not replace medical evaluation. Overall, the relationship is indirect and context-dependent; the evidence is rated as unclear.