Page:Popular Science Monthly Volume 89.djvu/826

 Why Do We Grow Bald?

Disease and tight hats are not the chief causes. Baldness can be inherited, Uke other traits

]>y I). Oshorn, Oliio State University

��IT IS popularly supposed that some forms of baldness are caused by the wearing of tight hats. Often the line of baldness seems to coincide with the hat-band, which might show that it is cutting off the supply of nourishment to the scalp. One of the main arguments in support of this theory is that women d become bald.

In making a study determine whether herediiy is an important factor, I considered only patter^i baldness. By pattern baldness is meant the kind associated with ihiii. normal or he:i\>' hair. 1 1 usualh" does not put in its appearance until after the twentieth year. Among the various patterns the most common are com- plete baldness on the top of the head ; that iinolv- ing only the crf)wn: thai giving the appearance of an extremely high fore- head, and that co\-cring the top and back portions of the he.id.

In one family the father was bald before he was thirty. His only son showed the same baldness pattern at birth, but later grew a normal head of hair, which he retained until the past \-ear. Now at twenty \ears of age the hair is beginning to fail out in the same fashion that his father's did. This indi- cates that the baldness pat- tern may be pl.iiiilydiTuied it birth.

In Iwofam- ilics which were studied, nr) baldness what e V e r could 1) e

���Obviously the liiii: of baldness here does not coincide with the hat-band

��found. Heavy hair predominated and was retained to an advanced age. Tight hats were worn by the men, but neither the hats nor severe illness had affected the luxuriance of the hair.

The families wiiich were traced in reference to baldness show clearly t is inherited. Contrar\' to prexalcnt belief, women do )ecome bald. They are mo;e sensitive concerning it, and can more easily conceal it than men. However, there are fewer bald women than bald men, due to the method of inheritance. Pattern bald- ness is called a "sex- limited trait." The char- acteristic is transmitted di- rectly from father to son and may be inheritetl through the mother, though she herself is not tiakl. A bald man may transmit the trait to hi-> d.uighier, who though she does not show it herself t to her children. A woman called a carrier. If a woman

���Till iiuiii on the rin'it is thiily livi ytjis old. The one on left is fifty. The patterns of baldness ore distinctly different

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��can transmit of this type i.\ inherits the tendency to baldness from both ])arents she herself becomes bald. Inherit- ing the tendency from both parents does not necess.irily mean that both parents must be bald, but that the father is bald

,iiul themolh- er a carrier. A bald wo- man must in- herit double the tendency that a bald man inherits. Th.it wom- en may be- have as carri- ers of bald- ness explains why it may ski|> genera- tii)ns and ap-

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