What role does TCF7L2 play in fertility?

TCF7L2 (transcription factor 7-like 2) is a key regulator of Wnt signaling and is strongly associated with type 2 diabetes risk via GWAS. Its direct role in fertility is poorly established. Some animal and in vitro studies suggest involvement in ovarian function and endometrial receptivity, but human evidence is weak and inconsistent. No robust clinical trials demonstrate a clear causal effect of TCF7L2 variants on female or male fertility. Most knowledge comes from diabetes research, where TCF7L2 variants impair insulin secretion – a possible indirect link to fertility through metabolic disturbances, but this remains speculative. Consumer DNA tests that include TCF7L2 should not be used for fertility guidance. The evidence is unclear and largely mechanistic. Caution: a positive finding does not indicate a fertility disorder.