Fig. 2. The process by which a single follicle is recognized (becomes dominant and achieves ovulation) occurs over the 14 days from onset of menses to the ovulatory event. The initial phase is recruitment, in which many follicles are stimulated by FSH. By about day 5 to 7, a single follicle has been selected as the one that proceeds to ovulation. This selected follicle is apparent only biochemically (e.g., estradiol secretion) and is not yet larger at this phase. Over the next 7 days, this selected follicle grows larger than the rest of the cohort and achieves special status and functional capabilities (becomes dominant).