Aitareyabrahmana 2.39

2.39

Having called, he recites the silent recitation; he thereby transforms the emitted semen.
First comes the emission, then the transformation.
He recites the silent recitation in an undertone; in an undertone, as it were, is the emission of semen.
He recites the silent recitation obliquely, as it were; obliquely, as it were, are the semens transformed.
He recites the silent recitation in six feet. Man is sixfold, having six limbs;
he thereby transforms himself into six parts, with six limbs.
Having recited the silent recitation, he recites the puroruc; he thereby brings forth the transformed semen.
First comes the transformation, then the birth.
He recites the puroruc aloud; aloud indeed he brings it forth.
He recites the puroruc in twelve feet.
Twelve months make the year, the year is Prajāpati;
he is the progenitor of all this.
He who is the progenitor of all this
brings him forth with offspring and cattle, for procreation.
He is propagated with offspring and cattle who knows thus.
He recites the puroruc addressed to Jātavedas, having an indication of Jātavedas.
Regarding this they say: "Since the third pressing is the abode of Jātavedas,
why then does he recite the puroruc addressed to Jātavedas at the morning pressing?"
Breath indeed is Jātavedas, for he knows what is born.
As many as are born of which he knows, they come to be;
and those of which he does not know, what would they be?
He who knows the self-consecration in the ājya, it is well known.