Brahmā is also named Aja, "he who is unborn." Whenever we think of someone's birth, there must be a material father and mother, for thus one is born. But Brahmā, being the first living creature within this universe, was born directly from the body of the Supreme Personality of Godhead who is known as Garbhodakaśāyī Viṣṇu, the Viṣṇu form lying down in the ocean at the bottom of the universe. Devahūti wanted to impress upon the Lord that when Brahmā wants to see Him, he has to meditate upon Him. "You are the seed of all creation," she said. "Although Brahmā was directly born from You, he still has to perform many years of meditation, and even then he cannot see You directly, face to face. Your body is lying within the vast water at the bottom of the universe, and thus You are known as Garbhodakaśāyī Viṣṇu."
(SRIMAD BHAGAVATAM--------3:33:2-----PURPORT).

------