"Devotee: Śrīla Prabhupāda, in a purport in the Śrīmad-Bhāgavatam you say that even fifty years ago in India the householders had separate apartments for the men and women.
Prabhupāda: Not apartment; quarter.
Devotee: Separate quarters in the apartment. And the husband would not see his wife during the day?
Makhanlāl: So is this the standard we should develop in our movement?
Prabhupāda: Yes, that is good. The example is the butter and fire should be kept separate as far as. . . Otherwise the butter will melt. Mātrā svasrā duhitrā vā (SB 9.19.17). The butter and. . . means man and woman. A man is butter, and woman is fire. So this is restricted even the man happens to be father, brother or son. Mātrā svasrā duhitrā vā. People cannot think of sex impulse in the presence of daughter, mother or sister. But śāstra says, "No. There is possibility.""