Mahabharata 12.328.45
ततो वै तमृषिश्रेष्ठं मैथुनोपगतं तथाउवाच गर्भः कौन्तेय पञ्चभूतसमन्वितः
tato vai tamṛṣiśreṣṭhaṃ maithunopagataṃ tathāuvāca garbhaḥ kaunteya pañcabhūtasamanvitaḥ
Our plain-language meaning of this verse is waiting for scholar review.
Open in the book