Pṛthivy-Āyāma-Vistara (Extent of the Earth) and Jambūdvīpa–Navavarṣa Description
मिथुनं जायते सद्यः समं चैव विवर्द्धते / समं शीलं च रूपं च प्रियता चैव तत्समा
mithunaṃ jāyate sadyaḥ samaṃ caiva vivarddhate / samaṃ śīlaṃ ca rūpaṃ ca priyatā caiva tatsamā
The pair is born at once and grows in perfect equality. Their nature and their beauty are alike, and so too is their mutual dear affection.