Final answer:
At birth, a female infant typically has one to two million oocytes in her ovaries, which declines to about 40,000 by puberty.
Step-by-step explanation:
At the time of birth, a female infant typically has about one to two million oocytes in her ovaries. These oocytes are within ovarian follicles, and this number declines naturally as she ages, through a process known as atresia. By the time she reaches puberty, approximately 40,000 oocytes remain. Throughout her reproductive years, oocytes develop from primary to secondary stages and ovulation occurs, typically releasing one mature oocyte (secondary oocyte) each month until menopause.