t is not complicated by the many incidental phenomena
which result, in man's case, from psychologic, economic, moral and
religious causes. Climate, social conditions, individual modes of life
and work, alcohol, wealth and poverty, and other factors affect sexual
activity in human beings.

Sexual love, which is practically unknown to the animals, is a special
development of the sex urge in the human soul. The deeper purpose of
the sex function in human beings, likewise, is procreation, the
reproduction of species.

The average man, woman and child should know the essential sex facts
in order to be able to deal with the sex problems of life. Of late
years there has been a greater diffusion of such knowledge. To a large
extent, however, children and adolescents are still taught to look on
all that pertains to sex as something shameful and immodest, something
not to be discussed. Sex is an "Avoided Subject."

This is fundamentally wrong. Sex affects the very root of all human
life. Its activities are not obscene, but Nature's own means to
certain legitimate ends. The sex functions, when properly controlled
and led into the proper channels, are a most essential and legitimate
form of physical self-expression. The veil of secrecy with which they
are so often shrouded tends to create an altogether false impression
regarding them. This discussion of these "Avoided Subjects," in "Plain
English," is intended to give the salient facts regarding sex in a
direct, straightforward manner, bearing in mind the true purpose of
normal sex activities.

The more we know of the facts of sex, the right and normal part sex
activities play in life, and all that tends to abuse and degrade them,
the better able we will be to make sex a factor for happiness in our
own lives and that of our descendants. Mankind, for its own general
good, must desire that reproduction--the real purpose of every sexual
function--occur in such a way as to perpetuate its own best physical
and mental qualities.

THE LAW OF PHYSICAL LIFE

It is a universal rule of physical life that every individual being
undergoes a development which we know as its individual life and
which, so far as its physical substance is concerned, ends with death.
Death is the destruction of the greater part of this individual
organism which, when death ensues, once more becomes lifeless matter.
Only small portions of this matter, the germ cells, continue to live