What causes pcos to develop?

No. Pcos is caused by increased insulin, Insulin resistance that is all part of the diabetes ii disease spectrum. Insulin increases male hormone (androgen) production in the ovary that inhibits follicle or egg development. Cycles are long, creating ovulation difficulty and fertility problems. This is a chronic disease with no cure, only maintenance control. Low carb high fat diet is best treatment.
Hormonal Problem. Pcos is caused by high estrogen (e2)combined with high Insulin which then transforms e2 into testosterone. Excess carbs can elevate both Insulin (via stimulation of pancreas) and e2 (via competitive inhibition of glucoronidase enzyme) a low carb diet reduces both Insulin & e2 thus positively impacting this metabolic disease. Avoid fried foods, veg oils, soy, hfcs, all sugar, excess starches.