Some scientists have concluded that male pattern baldness is handed down via a faulty gene through the male's maternal line. In other words, a man can get an idea of how his hair loss is likely to proceed from the appearance of men in his mother's family. The suspicious gene is in the X chromosome, which men inherit from their mothers.
Despite this research, hair loss has a number of other mitigating factors that affect how it progresses. Age is one major factor affecting hair loss. A man's chance of hair loss increases to about half when he passes the age of 50. Hair loss is actually related to an excess of the male hormone testosterone, which would normally produce more body hair, save for on the head, where it shows up as less.
Symptoms of hair loss typically come in the form of pattern baldness. This can include thinning hair, a receding hair line from the front to the back, a hair loss progression in an M pattern, or gradual hair loss from the crown of the head. Hair loss is the hair follicle becoming smaller and smaller over time. The hair ends up shorter and finer and then eventually becomes no hair at all.