Hair loss in men is a common occurrence. Sure, it happens more so in some men than others, but every man loses hair. The most common cause of hair loss in men is genetics. If either one of your parents experienced hair loss, you are far more susceptible to hair loss over the course of your life.
Hair loss in men is far more common than it is in women. Along with hair loss being hereditary, other common causes are mental and physical stress as well as age. Yes, stress does cause your hair to fall out. Even simple everyday stress can do this but it is much more prevalent in men who have high stress occupations.