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How does testosterone affect male reproductive development and secondary sex characteristics?

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human endocrine system The principal glands of the female and male human endocrine systems.

Testosterone is a primary androgen produced by the testes that is essential for male reproductive development and the expression of secondary sex characteristics.12

Reproductive Development

During fetal development, testosterone directs the transformation of the Wolffian ducts into the vas deferens and seminal vesicles. It is also critical for the descent of the testes into the scrotum. In many target tissues, testosterone is converted into the more potent dihydrotestosterone, which is responsible for the formation of the prostate gland and external genitalia.12

Secondary Sex Characteristics

At puberty, rising levels of testosterone stimulate the development of masculine traits, including:
* Growth of facial, axillary, pubic, and truncal hair.2
* Deepening of the voice.1
* Increased muscle mass and bone strength.12
* Scrotal pigmentation and prostatic enlargement.2
* Increased libido.2

Additionally, testosterone, in conjunction with follicle-stimulating hormone, supports spermatogenesis, the process by which the testes produce mature sperm.12