BṚHADĀRAṆYAKA UPANISHAD · 6.4.14

स य इच्छेत् -- पुत्रो मे शुक्लो जायेत वेदम् अनुब्रुवीत सर्वम् आयुर् इयाद् इति क्षीरौदनं पाचयित्वा सर्पिष्मन्तम् अश्नीयाताम् ।
ईश्वरौ जनयितवै ॥

sa ya icchet -- putro me śuklo jāyeta vedam anubruvīta sarvam āyur iyād iti kṣīraudanaṃ pācayitvā sarpiṣmantam aśnīyātām ।
īśvarau janayitavai ॥

In case one wishes, 'That a white son be born to me! that he be able to repeat a Veda! that he attain the full length of life!'--they two should have rice cooked with milk and should eat it prepared with ghee. They two are likely to beget [him].

Robert Ernest Hume · The Thirteen Principal Upanishads (1921), Bṛhadāraṇyaka VI.4