There are, however, serious fallacies in these contentions.

The propagandists of conception control appear to take it for granted
that after preventive measures in early youth, children may be
conceived at will whenever they are desired; and, moreover, it is
assumed that apart from such precautions every woman will conceive
annually and will continue to do so until 10-12 children have been
born.

Neither of these suppositions is supported by facts. On the contrary,
there are large numbers of married couples who would give anything to
have children, but have postponed it until circumstances should seem
quite desirable, and then, to their grief, no children are given to
them. It is very unfair to teach people that they may safely postpone
the natural tendency to bear children in youth and rely upon having
them later in life. Probably gynæcologists are consulted more often by
women who desire children but do not have them, than by those who
wish to avoid having them--the truth being that the tendency among
people in comfortable surroundings is towards relative sterility
rather than towards excessive fertility.

Those who are interested in this aspect of the question will find the
facts admirably set forth in Mr. Pell's book on _The Law of Births and
Deaths_, being a study of the variation in the degree of animal
fertility under the influence of environment.

He finds that the all-important factor which determines fertility is
the amount of nervous energy of the organism, and that nervous energy
is produced or modified by three specially influential factors, viz.,
Food, both quantity and quality; Climate, hot or cold--moist or dry;