“As the Supersoul of the living entities, I sit in everyone's heart and observe everyone's activity in every stage and order of life. Regardless of which stage one is in, when I see that one is engaged seriously and sincerely in discharging the duties ordered by the spiritual master and is thus dedicating his life to the service of the spiritual master, that person becomes most dear to Me. As far as the life of brahmacarya is concerned, if one can continue the life of a brahmacārī under the direction of a spiritual master, that is extremely good; but if in brahmacārī life one feels sex impulses, he should take leave of his spiritual master, satisfying him according to the guru's desire. According to the Vedic system, a gift is offered to the spiritual master, which is called guru-dakṣiṇā. Then the disciple should take to householder life and accept a wife according to religious rites.”
These instructions given by Lord Kṛṣṇa while talking with His friend the learned brāhmaṇa are very good for the guidance of human society. A system of human civilization that does not promote varṇa and āśrama is nothing but a polished animal society. Indulgence in sex life by a man or woman living single is never acceptable in human society. A man should strictly follow the principles of brahmacārī life or, with the permission of the spiritual master, should get married. Single life with illicit sex is animal life, for the animals have no such institution as marriage.
Modern society does not aim at fulfilling the mission of human life, which is to go back home, back to Godhead. To fulfill this mission, the system of varṇa and āśrama must be followed. When the system is followed rigidly and consciously, it fulfills this mission, but when followed indirectly, without the guidance of superior authority, it simply creates a disturbing condition in human society, and there is no peace and prosperity.