It is only animals that have to adapt themselves to their physical background and to the biological functions of their bodies. Man adapts his physical background and the use of his biological faculties to himself-to his own needs and values. That is his distinction from all other living species.
To an animal, the rearing of its young is a matter of temporary cycles. To man, it is a lifelong responsibility—a grave responsibility that must not be undertaken causelessly, thoughtlessly or accidentally.
In regard to the moral aspects of birth control, the primary right involved is not the "right" of an unborn child, nor of the family, nor of society, nor of God. The primary right is one which- in today's public clamor on the subject- few, if any, voices have had the courage to uphold: the right of man and woman to their own life and happiness—the right not to be regarded as the means to any end.
Man is an end in himself. Romantic love—the profound, exalted, lifelong passion that unites his mind and body in the sexual act—is the living testimony to that principle.
"Of Living Death", The Objectivist, p. 531