Polycystic Ovarian Syndrome (PCOS) affects, approximately, 1 in every 10 women. Since there is nothing that can definitively say that a woman has PCOS it makes it difficult to come up with exact statistics. The only thing medical professionals can do to give as accurate of a diagnosis as possible is to essentially do testing to rule out other possibilities. Once those possibilities are ruled out they can give a more accurate diagnosis.
There are studies that are currently going on to try and find out a way to accurately diagnose PCOS. It does not affect a specific race, it can affect women of all races. The women that do have PCOS are not born with it. PCOS only begins to affect women during and after puberty. This is because PCOS revolves around hormones, and ovulation.
Because of the hormone imbalance found in women with PCOS they have the access body hair. The hormones imbalance also leads to issues with ovulation, irregular periods, cysts on the ovaries, insulin resistance, etc. For those of you interested in why this is please take the time to look up how hormones are used in your body and what they affect. In particular testosterone, estrogen, and insulin. They are all intertwined and can cause a number of issues.

Mayo Clinic. (2017). Polycystic ovary syndrome (PCOS). Retrieved from             http://www.mayoclinic.org/diseases-conditions/pcos/home/ovc-20342146