The phrase “The Child is the father of Man” first appeared in a poem, “My Heart Leaps Up” by William Wordsworth in 1802.Meaning: 1. The true nature of a person doesn’t change with time or age. 2. The conduct of a child indicates what he will become when he grows up. 3. An adult is the product of the habits, manners and behavior that he inculcated during his childhood.