A nurse practitioner has just diagnosed a 14-year-old boy with Klinefelter syndrome. What is the most appropriate treatment?

Choice A reason: Estrogen is not indicated because Klinefelter syndrome involves low testosterone; giving estrogen could worsen feminization and does not address the underlying hormone deficiency. Choice B reason: Testosterone replacement therapy is the mainstay of treatment in Klinefelter syndrome to promote the development of secondary sexual characteristics, improve muscle mass and bone density, and support overall physical and psychological health. Choice C reason: Doing nothing would allow the effects of testosterone deficiency to persist, including delayed puberty, reduced muscle mass, decreased bone density, and potential psychosocial difficulties. Choice D reason: Progesterone is not used in Klinefelter syndrome; it does not address testosterone deficiency and has no role in managing the condition.