Final answer:
A low level of testosterone would cause a man to develop female secondary sex characteristics such as gynecomastia. Testosterone is responsible for male secondary sex characteristics, and an imbalance with estrogen can lead to such conditions.
Step-by-step explanation:
A low level of testosterone would cause a man to develop certain female secondary sex characteristics, like gynecomastia, where their breasts swell and become abnormally large. The male sex hormone testosterone is responsible for the development of male secondary sex characteristics such as a deepening of the voice, the growth of facial, axillary, and pubic hair, and the beginnings of the sex drive during adolescence. When testosterone levels are low, there might be an imbalance favoring estrogen, which can lead to the development of characteristics such as increased breast tissue. In contrast, hormones such as follicle-stimulating hormone (FSH), progesterone, and estrogen are associated with the female reproductive cycle and secondary sexual characteristics in females.