"Be fruitful and multiply," is more than a command, namely a divine work which it is not our prerogative to hinder or ignore. Rather, it is just as necessary as the fact that I am a man, and more necessary than sleeping and waking, eating and drinking. It is a nature and disposition just as innate as the organs involved in it.
Therefore, just as God creates us to be a man or a woman, so he creates us to multiply, not only as a natural function, but as a necessity for the prepetuation of His work on earth. Wherever men try to resist this, it remains irresistible nonetheless and goes its way through fornication, adultery, and secret sins. "Be fruitful and multiply," is a matter of nature and not of choice.
-Adapted from Charles Provan