In former days there were only two demons (Hiranyakasipu & Hiranyaksa)—those born of Diti—yet there were so many disturbances. At the present day, especially in this age of Kali, these troubles are always visible, which indicates that the demoniac population has certainly increased.
To check the increase of demoniac population, the Vedic civilization enacted so many rules and regulations of social life, the most important of which is the garbhadhana process for begetting good children. In Bhagavad-gita, Arjuna informed Krishna that if there is an unwanted population (Varna-Sankara), the entire world will appear to be hell. People are very anxious for peace in the world, but there are so many unwanted children born without the benefit of the garbhadhana ceremony, just like the demons born from Diti. Diti was so lusty that she forced her husband to copulate at a time which was inauspicious, and therefore the demons were born to create disturbances. In having a sex life to beget children, one should observe the process for begetting nice children; if each and every householder in every family observes the Vedic system, then there are nice children, not demons, and automatically there is peace in the world. If we do not follow regulations in life for social tranquility, we cannot expect peace. Rather, we will have to undergo the harsh reactions of natural laws.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Third Canto, Chapter 17 – Text 15