Male-pattern baldness, the most common type of hair loss that affects men, is indeed inherited, but the genes responsible for the condition have not been identified yet. In 2005, German researchers found a gene (located on the X chromosome that men inherit from their mothers) that may be involved in the process. But it is almost certain that other still-unidentified genes are also involved in baldness, possibly including some that are handed down by fathers.

In any case, a combination of genes that predispose a person to baldness probably exists in both men and women, but baldness is more common among men because baldness occurs if, in addition to the genes, the male hormone (testosterone) is present, and men have more circulating testosterones than women. Testosterone is produced by the testes in men and by the ovaries in women, but the testosterone produced by the ovaries is converted to estrogen, the female hormone, within the ovaries.

Testosterone is converted to dihydrotestosterone by an enzyme called type 2 5(alpha) reductase before it gets excreted from the body. Dihydrotestosterone causes the growth phase of the hair follicles in the scalp of adult men predisposed to baldness to shorten resulting in the production of hair that is very short and fine and that is prematurely shed.

There are a variety of ways to deal with baldness. Some men wear a toupee or undergo hair-weaving procedure, but these techniques do not offer a cure or permanent solution to the problem. Longer-lasting effects are offered by surgery and drugs.

A number of surgical hair-replacement techniques are currently used in the treatment of baldness, but they require a healthy growth of hair at the back and sides of the head, which will serve as hair donor areas. One technique involves transplanting small pieces of scalp from the back or sides of the head to the bald area. Another involves removing a part of the bald area and covering it with hair-bearing skin from the back or sides of the head. Still another technique involves removing areas of bald scalp, after which the hair-bearing portions of the scalp are pulled together to fill the areas that have been removed.

The results of hair-replacement surgery, however, are not always cosmetically acceptable. Many times the procedures produce patchy hair growth and/or wide scars.

Two drugs (minoxidil and finasteride) have demonstrated positive results in re-growing or preventing loss of scalp hair.

Minoxidil topical solution, when applied regularly on the scalp, reportedly leads to positive results in as many as 40 percent of patients, but often, the amount of hair re-growth is cosmetically unacceptable.

Finasteride, which is taken orally, has had better success. Finasteride has a hair-saving property because it prevents the conversion of testosterone to dihydrotestosterone.

In most patients treated with finasteride, further hair loss is prevented. In about half, hair re-growth occurs, but in only about a third is the re-growth cosmetically acceptable. Incidentally, the adverse effects of finasteride, which occur in about two percent of patients, include impotence, diminished libido, and decreased in the volume of ejaculate or semen. Also, finasteride can cause birth defects and should not be used for treatment of hair loss in women.

A very promising method of regrowing hair is presently being developed by a couple of companies. The method involves getting cells from hair follicles from the back of the neck, growing them in the laboratory, and then reimplanting the cells into the scalp. This treatment method could be available to the public in five years.

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