The mother is really a more immediate parent than the father because one is born from the mother, and the first experience of any infant is the mother.

Sexual pleasure, wisely used and not abused, may prove the stimulus and liberator of our finest and most exalted activities.

It is becoming clear that the old platitudes can no longer be maintained, and that if we wish to improve our morals we must first improve our knowledge.

Of woman as a real human being, with sexual needs and sexual responsibilities, morality has often known nothing.

Sex lies at the root of life, and we can never learn to reverence life until we know how to understand sex.

The mathematician has reached the highest rung on the ladder of human thought.

The relation of the individual person to the species he belongs to is the most intimate of all relations.