ignorant, the feeble-minded and the strong, the criminal and the righteous,
have been combined so frequently and in so many ways that the marvel
is that more of the human race are not degenerate as the result of
contamination. Since the great characteristic of heredity is to breed true
and thus perpetuate its kind, and since training and education must take
the individual as he is, with only limited power to change his intrinsic
nature or to develop any capacity not present at birth, it becomes a matter
of serious importance that parents do all in their power to guide properly
the mating of their children. The teaching of the Gospel on this point is
most significant.

Heredity determines to a great extent the kind and the nature of the
individual, and thereby sets limits, which the environment may not
overcome. Among these limitations are the following:

1. The relative strength of instincts.

2. The number and kind of capacities.

3. The form, size and quality of bodily organs.

4. Susceptibility to, or power to resist disease.

5. The possibilities of mental attainment.

6. The possibilities of emotional and spiritual response.

7. The possibility to execute undertakings, to control situations, and to
govern self as well as others.