I hope this is the right forum, since there was no general pediatrics option. My little boy is 6 months old this week and I'm concerned about some milestones that I keep reading about. People always comment that he is so alert and engaged and seems advanced, but he still will not "converse" with me. He smiled at 3 weeks, cooed and laughed at 2 months, and babbled at 4 months. But if I try to babble at him, he just stares at me and smiles. He has not once talked back, nor does he mimic any facial expressions. Should I be worried? As a side note: he mostly babbles mamamama when fussing--does that count? Physically, he is right on track if not slightly early.