Is LCT useful for fertility?

The question of whether the LCT gene (lactase persistence) is useful for fertility lacks solid scientific evidence. LCT determines the ability to digest lactose in adulthood—a purely nutritional trait. None of the provided knowledge contexts mention any link between LCT and fertility. Some marketing sources vaguely suggest that a lactose-free diet may improve conception, but such claims are not supported by clinical studies. The evidence is best rated as 'unclear' or 'marketing'. Individuals facing fertility issues should consult reproductive specialists rather than rely on genetic tests for lactose intolerance. An LCT test may be relevant for digestive discomfort but not for conception. Fertility genetics is polygenic and complex; LCT plays no established role.