Linked from
The 39 pages that link to Testosterone, each with the reason it gives.
Steroid hormoneBroader topic: It represents the androgen class of steroid hormones.
AndrogenBroader topic: It is the major circulating androgen in most adult men.
Male reproductive systemBroader topic: It is the principal androgen produced by the testes.
Facial hairBroader topic: Testosterone and its derivatives influence facial-hair development.