首楞嚴義疏注經 1.147

1.147

欲愛之生純是不淨，《大集經》中具說受生，皆由父母與己識情互生愛欲，由是託彼赤白二滴為識所依，一處和合名歌羅邏，而漸增長。至於出胎，五穀長養，雖成人相，如革囊盛糞，故云膿血雜亂。

The generation of desirous love is purely impure. The Mahāsaṃnipāta Sūtra fully explains receiving birth: it is entirely due to mutual desire arising between the parents and one's own consciousness. Based on this, relying on those two drops of red and white as the basis for consciousness, their blending in one place is called kalala, which gradually grows. Coming to emerge from the womb, nourished by the five grains, although one assumes human form, it is like a leather bag containing feces; hence it is called 'a chaotic blend of pus and blood.'