Ramayana
प्रयाते त्रिदिवं तस्मिन्निक्ष्वाकुरमितप्रभः । जनयिष्ये कथं पुत्रानिति चिन्तापरो ऽभवत् ॥ 7-79-12 ॥
When Manu had gone to the third heaven, Ikshvaku of measureless splendor became absorbed in anxious thought, wondering, "How shall I beget sons?"
english translation