King Yayāti was completely aware of the duty of a kṣatriya. When a kṣatriya is approached by a woman, he cannot deny her. This is a religious principle. Consequently, when Dharmarāja, Yudhiṣṭhira, saw Arjuna unhappy after Arjuna returned from Dvārakā, he asked whether Arjuna had refused a woman who had begged for a son. Although Mahārāja Yayāti remembered Śukrācārya’s warning, he could not refuse Śarmiṣṭhā. He thought it wise to give her a son, and thus he had sexual intercourse with her after her menstrual period. This kind of lust is not against religious principles. As stated in Bhagavad-gītā (7.11), dharmāviruddho bhūteṣu kāmo ’smi: sex life not contrary to the principles of religion is sanctioned by Kṛṣṇa. Because Śarmiṣṭhā, the daughter of a king, had begged Yayāti for a son, their combination was not lust but an act of religion.