The works of Ādi Śaṅkarācārya

Bṛhadāraṇyakopaniṣadbhāṣyam

Verse 299

रेतसा प्राणन्तः प्राणेन वदन्तो वाचा पश्यन्तश्चक्षुषा शृण्वन्तः श्रोत्रेण विद्वा-सो मनसैवमजीविष्मेति प्रविवेश ह रेतः ॥ १२ ॥

In plain words

...we couldn't father children, but we still breathed with breath, spoke with speech, saw with the eye, heard with the ear, and thought with the mind. That's how we lived.' So Seed came back in.

Close to the Sanskrit

...with semen, [but] breathing with the breath, speaking with speech, seeing with the eye, hearing with the ear, knowing with the mind — thus we lived.' Semen entered back in, indeed. [12]