Matsya Purana 195.8

195.8

devānāṃ mātaro dṛṣṭvā devapatnyastathaiva ca.
skannaṃ śukraṃ mahārāja! brahmaṇaḥ parameṣṭhinaḥ .. 195.7

First, all the Ṛiṣis went to heaven after casting away their corporeal bodies by the curse of Śiva There they were born of Brahmâ when the mothers and the consorts of the Devas saw the dripping of the semen virile of Brahmâ and caused it to be poured as oblation into the fire which produced the most illustrious sage Bhṛigu out of the fire.—6-8