What is the origin of the idiom "goo-goo eyes" and when to use it?

The origin of the idiom "goo-goo eyes" is uncertain, but it likely comes from the way infants or young children often stare with wide, innocent, and adoring eyes. The term "goo-goo" is a playful imitation of the sounds babies make, emphasizing the idea of childlike fascination and affection. The term is often used in a lighthearted or playful manner to describe a person's obvious or exaggerated display of romantic interest through their gaze. The idiom "goo-goo eyes" is considered old-fashioned. It was more commonly used in the past, particularly in the mid-20th century.