Procreation is the act or process of producing children or baby animals — the noun that sits beside procreate. You meet it in science, religion, and law, where people need a calm word for “making new life” without telling a family story. In everyday English it feels stiff; a doctor or a textbook may use it, a friend usually will not. Though actually, it is not a fancy synonym for “sex.” Sex can lead to procreation, but the word itself points at the result: new young, not the act that may cause it.