Final answer:
FSH is crucial for male fertility as it stimulates sperm production in the testes. The man's inability to synthesize adequate FSH may result in decreased spermatogenesis. Furthermore, the lack of prolactin in a woman primarily affects lactation post-childbirth rather than the ability to become pregnant.
Step-by-step explanation:
The issue of a man not synthesizing enough follicle-stimulating hormone (FSH) is critical because FSH is integral to male fertility. Among the four given statements, the correct one is that FSH stimulates sperm production in the testes. FSH works alongside another hormone, luteinizing hormone (LH), to maintain the reproductive system's proper function.
The hypothalamus releases gonadotropin-releasing hormone (GnRH), which signals the anterior pituitary gland to produce FSH and LH. In males, FSH acts on the Sertoli cells within the seminiferous tubules to promote spermatogenesis, the process of sperm cell development.
LH, also produced in response to GnRH, acts on Leydig cells in the testes to regulate testosterone production, which is essential for developing secondary sexual characteristics and facilitating sperm production. The regulation of FSH production is also influenced by inhibin, a hormone released by the testes, which signals to reduction in FSH release when sperm production is adequate. This regulatory feedback loop ensures that hormone levels and, therefore, fertility are maintained.
Women also produce FSH and LH, which regulate the ovarian cycle. In the case of a woman not producing enough prolactin, it affects lactation rather than fertility directly. While prolactin is essential for milk production post-childbirth, its insufficient levels primarily impact the ability to nurse rather than the ability to conceive or carry a pregnancy to term.