Purpose of review <p>For women who are of reproductive age, the most prevalent hormonal condition is called polycystic ovarian syndrome, or PCOS. Estrogen is a vital hormone that controls the processes involved in female reproduction related to the emergence of sexual characteristics during adolescence and sexual maturity. The purpose of the review is to present a comprehensive molecular understanding of the functions of estrogen and estrogen receptors (ERs) in the pathophysiology of PCOS. In order to clarify the ways in which abnormal ER and estrogen actions contribute to the onset and advancement of PCOS. The review provides contemporary understanding of estrogen signaling pathways.</p> Recent findings <p>The particular receptors referred to as estrogen receptors (ERs) are responsible for controlling gene expression by stimulating signaling mechanisms and/or transcriptional processes in response to estrogen. These effects may result in direct attachment of complexes of estrogen receptors to certain regions in gene promoters that don't attach to DNA directly. Regardless of whether estrogens act through the impact of indirect non-nuclear activities, direct nuclear mechanism, or a mix of both on gene expression is governed by complex and tightly controlled systems.</p> Summary <p>When the overproduction of estrogen occurs or when the function of estrogen receptors 1 and 2 (ESRs 1) is impaired, this can lead to extreme signaling reactions that can cause PCOS and along with other pathologies, such as breast and endometrial cancers.</p>