SB 5.17.15
ilavrte tu bhagavan bhava eka eva puman na hy anyas tatraparo nirvisati bhavanyah sapa-nimitta-jño yat-praveksyatah stri-bhavas tat pascad vaksyami.
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Sukadeva Gosvami said: In the tract of land known as Ilavrta-varsa, the only male person is Lord Siva, the most powerful demigod. Goddess Durga, the wife of Lord Siva, does not like any man to enter that land. If any foolish man dares to do so, she immediately turns him into a woman. I shall explain this later [in the Ninth Canto of Srimad-Bhagavatam].