Comment. While I don't mind the idea of describing the variability of the menstrual cycle in detail, I wish to caution editors about the use of the primary literature. It is not as simple as just picking and presenting a grand average. If you look very closely at the classic studies (e.g., Gunn et al., Chiazze et al.), you will notice that 1) the sample distributions in those studies are skewed and never normal, i.e., bell-curved shaped, 2) there is a greater variability when the average is taken at 29 days and less variability when taken at 28 days, 3) the so called 28 day average is often the modal number and 4) other high quality and acceptable sources designate 28 days as the average. So presenting just one average number from a small set of studies without any context is very misleading and simplistic. Cherry picking a set of numbers, etc often leads to original research (WP:OR) or POV pushing, which is against WP policy. Again, we should follow WP policy and stick primarily to mainstream secondary sources that are representative of the mainstream literature.