The Polycystic Ovary Syndrome and recent human evolution.

The Polycystic Ovary Syndrome (PCOS) is a complex endocrine disorder characterised both by reproductive and metabolic disturbance, and is the most common cause globally of ovarian infertility. It is also a familial polygenic condition, linked genetically to both Type 2 diabetes and the metabolic syndrome. The striking evolutionary paradox of this prominent genetically-based condition, which impairs fertility, is that not only should it have diminished in prevalence, but it should have done so rapidly - unless there has been some form of balancing selection. The emerging discipline of evolutionary medicine can provide important insights into the causes and patterns of occurrence of common diseases such as PCOS. In this paper we review the impacts of PCOS on infertility, fecundability and lifetime reproductive success and then critically appraise published hypotheses about the evolutionary origins of PCOS and related conditions.