तस्मिन्नेतस्मिन्नग्नौ देवा रेतो जुह्वति तस्या आहुतेर्गर्भः सम्भवति ॥ २ ॥
In plain words
In this very fire the gods offer the seed, and from that offering an embryo is born.
Close to the Sanskrit
In that very fire the gods offer seed. From that oblation an embryo comes into being.