Osborn: Inheritance of Baldness 
In chart 3 the trait is inherited for 
four generations, directly from father 
to son. II 5 became very bald at 
forty, as did both of his sons, III 5 
and III 6, and also his grandson, IV 4. 
In the families charted, where the 
inheritance is direct from father to 
son, the pattern and age of appearance 
vary slightly in succeeding generations. 
In this case in chart 3 baldness covers 
the entire top of the head and extends 
down almost to the neck. The hair is 
lost at about forty years of age. II 8 
inherited baldness ‘from his father, 
I 2, but accurate information could not 
ber secured. IV a, a-woman, has) a 
bald spot at the back of her head. 
Her father, III 4, was bald and her 
mother, III 3, was a carrier, inheriting 
the “trait fron her father, 11 .1.. <The 
daughter, IV 1, inherits a duplex con- 
dition, as both parents transmit the 
trait.~ Neither of her sisters, IV 2 and 
IV. 3, 1s. bald: The: expectation .of 
baldness in the daughters from a 
mating of this description would be 
one in four. 
Chart 4 shows many interesting 
conditions. I 2 became bald at rather 
an early age and had quite an extensive 
pattern. Her four sons, II 3 and II 4, 
by the first, and II 6 and II 8, by the 
second marriage, were all bald. Un- 
fortunately little is known of. the first 
two, but the two latter showed the 
same pattern as their mother. Having 
all of her sons bald would indicate that 
she herself was homozygous for the 
trait. In the families studied this holds 
good for two of the other three bald 
women, who married and had sons. 
The fourth bald woman, not charted, 
had typhoid fever when she was forty 
and afterwards lost the hair on the 
front of her head. Her father: was 
bald. Five of her nine sons were cer- 
tainly bald, two are questionable, and 
two were not. This is a case of bald- 
ness in a woman caused. by ill health in 
addition to an inherited tendency. 
Returning to chart 4, II 5 was bald, 
inheriting only the simplex condition, 
but upon inquiry it was ascertained 
that she had poor health all of her life 
and did not become bald until rather 
late. Her sister, IT 9, may also have 
opt 
been bald, but data concerning her are 
too uncertain to put her down as such. 
Her two sons, III 15 and III 16, were 
both bald. II 2 must be a carrier, as . 
one son, III 9, is bald and one daughter, 
Iit-.3, is a cartier, transmitting the 
trait to one son, IV 2. III 9 is bald 
and IIT 10 is a carrier, as is shown by 
the amount of baldness in their children. 
HIS BROTHERS ARE BALD 
This individual, age 31, has a heavy head 
of coarse hair. His two younger 
brothers are bald—one at the age of 
22. His father is bald but his moth- 
er’s family showed no_ baldness. 
The individual here shown evidently 
did not inherit the bald pattern, and 
therefore retains his hair in spite of 
the fact that he has had typhoid 
fever and other illness, and therefore 
has had every chance to express the 
inheritance if he had it. Obviously, 
baldness is a segregating character 
which may go to some of a family, 
but not to all unless it comes from 
both sides of the ancestry. (Fig. 5.) 
Fourssons, EViesS, TV - 9)) dV.) 12. aad 
IV 13, are all bald. The other two 
sons, IV 14 and IV 15, are still too 
young to show whether they have 
inherited the trait or not. A daughter, 
IV 10, has recently become bald. She 
inherits the duplex condition because 
both of her parents transmit the trait. 
Another daughter, IV 11, shows no 
signs of baldness. 
In chart 5 there is shown an unusual 
number of bald women. I 1 was com- 
pletely bald; I 2 is questionable; II 2 
was partly bald; while IJ 3 and II 4 
were completely bald. II 1, husband 
