A man may not have chest hair due to a deficiency in a particular androgen, according to the Better Health Channel from the State Government of Victoria. Androgen is the technical term for the collective group of male hormones. This group includes more specific male hormones such as testosterone or androsterone.

With a deficiency in a male sex hormone, a man may not have the capability of growing hair in particular areas. Male sex hormones are responsible for the regulation of hair growth and other developmental processes. The most significant androgen is testosterone. Testosterone plays a role in bodily functions such as muscle development, prostate function and hair growth, explains the Better Health Channel. A deficiency in this hormone impedes these bodily functions, leading to many symptoms including hair loss.

The technical term for a testosterone deficiency is hypogonadism, notes Vertical Health. Natural aging, pituitary gland defects and medications are among the leading causes of hypogonadism. A man who does not have chest hair or who is in the process of losing chest hair may want to consider testing for this condition. Genetics and certain medications are also known to cause this condition. Other symptoms that may signal hypogonadism include decreased libido, fatigue and mild breast development.