Śatapatha Brāhmaṇa ("of a hundred paths") 1.9.2.11

1.9.2.11

atha devānām patnīryajati | patnīṣu vai yonau retaḥ pratiṣṭhitaṃ tattataḥ prajāyate tatpatnīṣvaivaitadyonau retaḥ siktam pratiṣṭhāpayati tattataḥ prajāyate tasmāddevānām patnīryajati

He then makes offering to the wives of the gods. In the wives, in the womb, the seed assuredly is planted, and thence it is produced; hence he thereby plants the seed in the wives, in the womb; and thence it is produced: for this reason he makes offering to the wives of the gods.