There are many myths regarding the possible causes of baldness and its relationship with one's virility, intelligence, ethnicity, job, social class, wealth, etc. While skepticism is warranted due to lack of scientific validation, some of these myths may have a degree of underlying truth.

"You inherit baldness from your mother's father"

Previously, early baldness of the androgenic type was thought to be sex linked dominant in males and to be sex linked recessive in females. Research suggests that the gene for the androgen receptor, which is significant in determining probability for hair loss, is located on the X chromosome and so is always inherited from the mother's side. There is a 50% chance that a person shares the same X chromosome as their maternal grandfather. Because women have two X chromosomes, they have two copies of the androgen receptor gene while men only have one. However research has also shown that a person with a balding father also has a significantly greater chance of experiencing hair loss.

"Baldness can be caused by emotional stress, sexual frustration etc."

Emotional stress has been shown to accelerate baldness in genetically susceptible individuals. Stress due to sleep deprivation in some studies, lowered testosterone levels, but is not noted to have effected sex hormone binding gobulin SHBG.
Thus, stress due to sleep deprivation in fit males is unlikely to elevate DHT, which causes male pattern baldness. Whether it can cause hair loss by some other mechanism is not clear.

"Bald men are more "virile" or sexually active than others"

Levels of free testosterone are strongly linked to libido and also DHT levels, but unless free testosterone is virtually non-existent, levels have not been shown to affect virility. Men with androgenic alopecia are more likely to have a higher baseline of free androgens. However sexual activity is multifactoral, and androgenic profile is also not the only determining factor in baldness. Additionally, because hair loss is progressive and free testosterone declines with age, a person's hairline may be more indicative of their past than present disposition.