Shiva Purana
पुरुषत्वादिगर्भो हि गर्भवाञ्जनको यतः । पुरुषात्प्रकृतो युक्तं प्रथमं जन्म कथ्यते ९७ ।
Since it is the father who conceives first, the Puruṣa has the primordial conception. The unification of Puruṣa and Prakṛti is the first birth.
english translation
puruSatvAdigarbho hi garbhavAJjanako yataH । puruSAtprakRto yuktaM prathamaM janma kathyate 97 ।
hk transliteration by Sanscript