Why Do Some Men Have No Chest Hair?
Bodies come in all shapes and sizes, and even levels of furriness. Some men experience increased hair growth in the early years of puberty, while others, depending on hormones, environment and genetics, can remain virtually hair-free into their late 20s.
Causes of Hair Growth
There are three causes of hair growth in men. Since hair growth is considered a secondary sex characteristic (related to the development of human sexuality by gender), it is closely related to age and hormones. Environment, where you live and are raised, and genetics, or the biological materials passed down through your parents, can also affect whether you will grow a lot of chest hair or very little chest hair.
Androgens are special hormones that play the largest part in developing primary and secondary sex characteristics in men and women. The most well known androgen is testosterone (the predominantly male hormone), which is closely related to estrogen (the predominantly female hormone). Androgens are mainly in charge of developing and regulating growth processes of organs and body hair.
A person’s environment, which can include climate and temperature, can also influence the amount of hair that will grow on the chest. In colder climates, humans have developed a need for more hair as means for regulating body temperature. The opposite is true in warmer areas, where the climate does not favor cold-climate adaptations.
Genetics, or the genetic material passed on to a person by his or her parents, is also a large factor in determining amounts of chest and other body hair. A family of relatively little-haired men will be less likely to pass down high levels of androgens to the children. Likewise, a family that tends to have high levels of androgens will most likely pass down that genetic predisposition.
Over time, a significant change in any of the three aforementioned factors can inhibit or encourage hair growth. The best source for answers is the person’s primary care physician, who could run a full test of hormonal levels as well as take into account the person’s environmental and genetic predispositions.