Householders who beget children without restriction, like weeds in the rainy season, become solitary as soon as they attain to the stage of devotional service.
The family planning of a godless civilization cannot check weedlike unwanted population. People should learn to check sex life by voluntary restraint. This voluntary restraint is possible when one is dovetailed with the service of the Lord.
This is confirmed in Bhagavad-gita. Well-situated devotees of the Lord refrain from materialistic sense enjoyment, for they are attracted by the beauty of the Transcendence.
Forcible restraint by regulative family planning or similar artificial means cannot work very long; one must be attracted by the Transcendence.
Once can give up the inferior quality of enjoyment as soon as one receives the superior quality of spiritual enjoyment. So family planning is successful when one is engaged in the culture of the human spirit.
Light of the Bhagavata
by His Divine Grace A. C. Bhaktivedanta Swami Prabhupada