Aitareya Āraṇyaka 2.5

2.5.p1

puruṣe ha vā ayam ādito garbho bhavati \
yad etad retas, tad eta/t sarvebhyo 'ṅgebhyas tejaḥ saṃbhūtam ātmany evātmānaṃ bibharti.
tad yadā striyāṃ siñcaty, athainaj janayati \
tad asya prathamaṃ janma \
tat striyā ātmabhūyaṃ gachati, yathā svam aṅgaṃ tathā \
tasmād enāṃ na hinasti \
sāsyaita/m ātmānam atra gataṃ bhāvayati.
sā bhāvayitrī bhāvayitavyā bhavati \
taṃ strī garbhaṃ bibharti.
so 'gra eva kumāraṃ janmano 'gre 'dhibhāva/yati \
sa yat kumāraṃ janmano 'gre 'dhibhāvayaty, ātmānam eva tad bhāva/yati \
eṣāṃ lokānāṃ saṃtatyā.
evaṃ saṃtatā hīme lokāḥ \
tad asya dvitīyaṃ janma \
so 'syāyam ātmā puṇyebhyaḥ karmabhyaḥ pratidhīyate \
athāsyāyam itara ātmā kṛtakṛtyo vayogataḥ praiti \
sa itaḥ prayann eva punar jāyate \
tad asya tṛtīyaṃ janma \
tad uktam ṛ/ṣiṇā \
garbhe nu sann anv eṣām avedam (RV IV 27,1a), ahaṃ devānāṃ janimāni viśvā (RV IV 27,1b) \ śataṃ mā pura āyasīr arakṣann (RV IV 27,1c), adha śyeno javasā nir adīyam (RV IV 27,1d) iti \\
garbha evaitac chayāno vāmadeva evam uvāca \
sa evaṃ vidvān asmā/c charīrabhedād ūrdhva utkramyāmuṣmin svarge loke sarvān kāmān āptvā/mṛtaḥ samabhavat, samabhavat \
\\ ity aitareyadvitīyāraṇyake pañcamo 'dhyāyaḥ \\

Verily, from the beginning he (the self) is in man as a germ, which is called seed.

This (seed), which is strength gathered from all the limbs of the body, he (the man) bears as self in his self (body). When he commits the seed to the woman, then he (the father) causes it to be born. That is his first birth. (1)

That seed becomes the self of the woman, as if one of her own limbs. Therefore it does not injure her.

She nourishes his (her husband's) self (the son) within her. (2) She who nourishes, is to be nourished.

The woman bears the germ. He (the father) elevates the child even before the birth, and immediately after.

When he thus elevates the child both before and after his birth, he really elevates his own self,

For the continuation of these worlds (men). For thus are these worlds continued.

This is his second birth. (3)

He (the son), being his self, is then placed in his stead for (the performance of) all good works.

But his other self (the father), having done all he has to do, and having reached the full measure of his life, departs.

And departing from hence he is born again. That is his third birth.

And this has been declared by a Rishi (Rv. IV, 27, 1): (4)

'While dwelling in the womb, I discovered all the births of these Devas. A hundred iron strongholds kept me, but I escaped quickly down like a falcon.'

Vâmadeva, lying in the womb, has thus declared this. (5)
And having this knowledge he stepped forth, after this dissolution of the body, and having obtained all his desires in that heavenly world, became immortal, yea, he became immortal. (6)