From Dr Lee's website:
D.13 Myth: Pattern Baldness Comes from Your Mother's Side Only
Yes and no. It's an enduring and common misconception among patients that male pattern baldness is 'inherited from the mother's side'. Well, that statement is neither right nor wrong. Pattern baldness can be inherited from the mother's side. But it can also be inherited from the father's side.
Despite the fact that the entire human genome, comprising approximately 30,000 genes in the human DNA, was completely mapped out as of April 2003, the gene or, more likely, genes responsible for male pattern baldness, have not been identified. What is known is that the age of onset, the rate of progression, and the pattern of follicular miniaturization are all influenced by heredity. Generally, the earlier the onset of balding, the more extensive the degree of hair loss will eventually be.
Considering the high proportion of men affected by male pattern baldness, its distribution in the general population, the increased risk of male pattern baldness as the number of affected close relatives increases, and the high risk of inheritance from either or both affected parents, one can support a strong argument in favor of an autosomal, polygenic inheritance.
It seems ironic that with all the knowledge that has been accumulated in regards to male pattern baldness in the past several decades, we still do not know the exact genetic inheritance of male pattern baldness. What is known is that the genes are autosomal (not on the X or Y chromosomes), dominant (as opposed to recessive), and have variable penetrance (so it may not affect siblings of the same parents to the same degree).
However, in a recent article on WebMD (
http://webcenter.health.webmd.netscape. ... 108259.htm) entitled "Blame Male Pattern Baldness on Mom?" the authors have found a gene variation that may explain some cases of male pattern baldness. The suspect gene variation sits on the X chromosome, which is handed down to men by their mother. It had been previously presumed that the genes involved in the transmission of male pattern baldness were always autosomal.
The genes for hereditary hair loss are carried on both sides of the family. And the tendency to hereditary hair loss can skip generations. If many close members of the family are afflicted with male pattern baldness, the greater the likelihood is that you will also have male pattern baldness. On the other hand, if they all have full heads of hair, it's likely you'll keep yours as well.