According to the Vedic system, one has to forcibly give up family life at the age of fifty. One must go. There is no alternative. The first twenty-five years are for student life. From age five to age twenty-five, one should be educated very nicely in Krsna consciousness. The basic principle of one's education should be Krsna consciousness, nothing else. Then life will be pleasing and successful, both in this world and in the next. A Krsna conscious education means one is trained to give up material consciousness altogether. That is perfect Krsna consciousness.
But if the student is unable to capture the essence of Krsna consciousness, then he is allowed to marry a good wife and live a peaceful householder life. And because he has been trained in the basic principles of Krsna consciousness, he will not entangle himself in the material world. One who lives simply–plain living and high thinking–can make progress in Krsna consciousness even within family life.
So family life is not condemned. But if a man forgets his spiritual identity and simply becomes entangled in material affairs, then he is lost. His life's mission is lost. If one thinks, "I cannot protect myself from the attack of sex desire," then let him be married. That is prescribed. But don't have illicit sex. If you want a girl, if you want a boy, get married and live in Krsna consciousness.
From: Transcendental Teachings of Prahlada Maharaja by Srila Prabhupada