How are CLOCK and fertility related?

CLOCK genes are core components of the circadian rhythm and regulate numerous hormonal pathways, including those involved in reproduction. Animal models and observational human studies suggest that circadian disruption – e.g., from shift work or sleep deprivation – may impair fertility by altering sex hormone levels, menstrual cycle regularity, and oocyte quality. However, the evidence is largely mechanistic; robust clinical trials directly linking specific CLOCK variants to fertility outcomes are lacking. A consumer DNA test for CLOCK polymorphisms cannot diagnose or predict fertility. The interplay between circadian genes and reproduction is complex and influenced by many non-genetic factors. Individuals with fertility concerns should consult a healthcare provider rather than rely on genetic testing. The current evidence does not support clinical use of CLOCK genotyping for fertility assessment.