Śatapatha Brāhmaṇa ("of a hundred paths") 5.1.3.10

5.1.3.10

sarve muṣkarāḥ | prajananaṃ vai muṣkaraḥ prajananam prajāpatiḥ prājāpatyā ete tasmātsarve muṣkarā bhavanti durvedā evaṃsamṛddhāḥ paśavo yadyevaṃsamṛddhānna vindedapi katipayā evaivaṃsamṛddhāḥ syuḥ sarvamu hyevedam prajāpatiḥ

They are all males;--for the male means productiveness, and Pragâpati represents productiveness: hence they are all males. Difficult to obtain are victims with these perfections: if he cannot obtain them (all) with these perfections, even some with these perfections will do; for verily Pragâpati is everything here.