We undertook a systematic search through PubMed and PubMed Central in August 2022, using keywords such as "polycystic ovary syndrome", "type 2 diabetes", (polycystic ovary syndrome (title/abstract)) OR (PCOS title/abstract) OR (insulin resistant *(title/abstract)) OR ("polycystic ovary syndrome" (MeSH Terms)) AND (("hyperandrogenism" (title/abstract)) OR (type 2 diabetes (title/abstract)) OR (insulin resistant" (MeSH Terms)). This evidence concerns the gene INS and polycystic ovary syndrome.