Prabhupada's lecture Śrīmad-Bhāgavatam 1.8.35 - Māyāpura, October 15, 1974
So why? Ignorance. Ignorance. So therefore this very word is used, avidyā. He never thinks... He is so much absorbed in ignorance that he has no time to think that "Repeatedly I am stealing, and repeatedly I am arrested, and I am punished. I sent to jail. Why I am doing this?" Result is not very good. Just like a person too much sexually inclined. He suffers in so many venereal diseases, undergoes operation, and still, he goes to prostitute, again does the same thing. This is avaidha-strī-saṅga, illegitimate. And legitimate also. After sex, the woman is pregnant, and she has to suffer for ten months. And at the time of delivery it is very dangerous sometimes. And the man also, after he gets the child, he has to take care of the child. He has to work hard to give education. This is proper, proper sex. The proper sex there are so many difficulties. And what is the..., what to speak of the improper sex? You kill the child. You take contraceptive.
You make this; you make that. Therefore śāstra says, bahu-duḥkha-bhājaḥ. After sex life, oh, there are so many troubles, bahu-duḥkha-bhājaḥ, simply trouble, either legitimate or illegitimate, simply trouble. Tṛpyanti neha kṛpaṇā. But because he is a rascal, ignorant, he's not satisfied, again does the same thing. Punaḥ punaś carvita-carvaṇānām [SB 7.5.30]. Again. This is called bhava-roga. Yan maithunādi-gṛhamedhi-sukhaṁ hi tuccham, kaṇḍūyanena karayor iva duḥkha-duḥkham [SB 7.9.45]. Iva duḥkha-duḥkham. Simply trouble. Therefore Vedic civilization is to train these small boys to remain brahmacārī, not to take trouble. But if one is unable, he's allowed. So on being trained up in the beginning as brahmacārī, he does not stay for many years in the family life. He retires very soon and becomes vānaprastha, then sannyāsa. That is the training.