Which hormone is primarily responsible for the development of male characteristics?

Testosterone is the primary hormone responsible for the development of male characteristics. It is an androgen, a group of hormones that play a role in male traits and reproductive activity. Testes produce testosterone, which leads to the development of secondary sexual characteristics during puberty, such as increased muscle mass, facial hair, and a deeper voice. Additionally, testosterone is essential for regulating various functions in the male reproductive system, including sperm production and libido.

The other hormones mentioned, such as LH (luteinizing hormone) and FSH (follicle-stimulating hormone), are involved in the regulation of the reproductive system but do not directly cause the development of male characteristics. LH stimulates the production of testosterone from the Leydig cells in the testes, while FSH primarily acts on the testes to promote spermatogenesis. Oestrogen, on the other hand, is more conventionally associated with female characteristics and reproductive functions, though it is present in males as well but at lower levels.