Srimad-Bhagavatam: Canto 3 - Chapter 1 - Verse 55
Sanskrit:
तदा मिथुनधर्मेण प्रजा ह्येधाम्बभूविरे ॥ ५५ ॥
ITRANS:
tadā mithuna-dharmeṇaprajā hy edhām babhūvire
Translation:
Thereafter, by sex indulgence, they gradually increased generations of population one after another.