ful development of the full powers of their bodies in future
years; that internal secretions of these organs coming into the blood help
to build up bones and muscles, help to make their nerve fibers active and
vigorous, help to form their brains, and help to equip them for manly
strength and womanly grace in the years that are to come. These are very
simple matters. These facts of sex can be conveyed by just a few sentences
of clear, considerate, wise information at the right time, in relation to
the other facts of bodily development.

Considering now the period of puberty, we find additional needs, for no
boy or girl reaches puberty, under ordinary conditions, without knowing
that it brings the possibility of fatherhood and motherhood, brings the
possibility of that process that we call fertilization, in which the life
of plants and animals begins. The boy or girl who reaches this age has a
right to know what fertilization means, and what fertilization implies;
has a right to the simple biological facts which will tell him the
relation between the life of the parents and the life of the child, the
mysterious relation in body and mind that we call heredity. The beginning
of the socializing of sex energy and sex power depends upon recognition of
the fact that this power that develops in the young man and young woman at
puberty is not to be used for selfish gratification, is not primarily a
source of pleasure, but has a very direct relation to the health,
intelligence, and happiness of others. This relation may be enforced by a
simple study of succeeding generations of flowers and the ways in which
forms, colors, and sizes originate and are handed down from generation to
generation in wonderful variety. Or it may be illustrated from an
observation of the beginnings of sex in infusoria; how tiny animals in
stagnant water grow to full size and each divides simply into two to form
a new generation; how this simple asexual process continuing for several
generations results in growing weakness and old age, steadily decreasing
size, steadily decreasing vitality until there comes a time when one
infusorian unites with another. There sex begins. That union of two
individuals is required to restore youth, to refresh vitality and energy,
and to produce greater variety in the forms of life. When a boy or girl
knows these simple facts, he is better able to understand the power of
reproduction than he can possibly be if they are not bef