Baby Boy Giggles - Insult or compliment?

Yesterday we went to Ikea to meet my Sister, Cousin and Baby Cousin and our Mother for a "treat" in the cafe.

Baby Boy was sitting opposite my Sister who was breast feeding Baby Cousin (nearly six weeks old). Baby Boy looked as Sister and shouted "Boob!" and then went back to eating his fruit slices and staring at a couple of women deep in conversation at the next table.