What is the primary effect of follicle-stimulating hormone (FSH)?

The primary effect of follicle-stimulating hormone (FSH) centers around its critical role in reproductive health and development. FSH is produced by the anterior pituitary gland and influences the growth and maturation of ovarian follicles in females and stimulates spermatogenesis in males.

In females, FSH is essential for the initiation of ovarian follicle growth, promoting the development of the ovarian follicles and the secretion of estrogen. This makes option B particularly relevant, as it accurately describes FSH's effect in female physiology. FSH acts on the granulosa cells in the ovaries, leading to the maturation of the oocyte and the production of hormones necessary for the menstrual cycle.

In males, while FSH does not stimulate testosterone directly, it does play a role in the regulation of spermatogenesis by acting on Sertoli cells, providing support for the development of sperm cells. This is crucial for fertility but does not directly correlate with testosterone development as suggested in option A.

The hormone does not directly initiate milk production, which is primarily stimulated by prolactin, nor does it cause ovulation, which is triggered by a surge in luteinizing hormone (LH) rather than FSH. Therefore, the best characterization of FSH's primary action focuses on