term Masculinity, which
conveniently expresses the proportion of the sexes at birth. The
degree of masculinity is usually indicated by the average number of
male births to every 100 female births. The cause of this
preponderance of males is still a mystery, and will definitely be
known only when the causes of the determination of sex are known.
Since, however, it is well known that infant mortality is greater
among males than among females, positive masculinity is necessary to
keep up the balance of the sexes, and therefore seems to be an
essential characteristic of a vigorous and progressive race.

Within recent years the theory has prevailed among certain
sociologists that positive masculinity is stronger in the offspring of
consanguineous marriages than in the offspring of unrelated parents.
Professor William I. Thomas in his writings and lectures asserts this
as highly probable.[28] Westermarck,[29] to whom Professor Thomas
refers, quotes authorities to show that certain self-fertilized plants
tend to produce male flowers, and that the mating of horses of the
same coat color tends to produce an excess of males.[30]

[Footnote 28: _Sex and Society_, p. 12.]

[Footnote 29: _History of Human Marriage_, p. 476.]

[Footnote 30: _Goehlert, Ueber die Vererbung der Haarfarben bei den
Pferden._ Quoted by Westermarck, p. 476.]

Westermarck continues, quoting from Duesing:[31] "Among the Jews, many
of whom marry cousins, there is a remarkable excess of male births. In
country districts, where, as we have seen, comparatively more boys are
born than in towns, marriage more frequently takes place between
kinsfolk. It is for a similar reason that illegitimate unions show a
tendency to produce female births."

[Footnote 31: _Die Regulierung des Geschlechtsverhaeltnisses_, pp.
243-244.]

Westermarck comments: "The evidence for the correctness of his
deduction is, then, exceedingly scanty--if, indeed it can be called
evidence. Nevertheless, I think his main conclusion holds good.
Independently of his reasoning I had come to exactly the same result
in a purely inductive way." He then quotes a number of travelers to
the effect that marriage between members of different races produce a
phenomenal excess of female births. When we consider the extraordinary
proficiency in fiction attained by many travelers in strange lands, we
are forced to the belief that Westermarck based his own conclusion on
still more scanty evidence.

The