So how much by nature the sex life is condemned in so many ways. Therefore we say, "No illicit sex." It will save you from so many encumbrances. Sex life is not denied, but this unrestricted sex life is very, very abominable in human society. But they are encouraging unrestricted sex life. They are distributing tablet, encouraging others to have sex life, never mind. Unmarried girls, they are keeping dogs. One lady in America, she told me that the dogs are kept for this purpose. When I was going to walk in that park in Brooklyn, the young girls are bringing dogs, big, big dogs.

…

So this syphilitic disease is mentioned in the Ayur Veda, the disease brought by the phiringis. And the doctor says that originally it was spread through dog. The unmarried girls, they keep dog for sex. You do not know? He knows. You will find very beautiful girl is keeping very big dog. They are trained to have sex life. And that is cause of syphilis. The dog is full of syphilitic germs.

From Srila Prabhupada's lecture on Srimad-Bhagavatam 2.9.1–9 — April 27, 1972, Tokyo