My son is 2.5 years old. When he was 9 months old, he developed a phobia of other children--from newborns up to toddler-aged. In all other respects, he is a normally-developing child. He has never been afraid of adults at all, in fact, would seek them out from an early age and engage them in play. With kids about age 4 and older--if they can speak like big people and play with him, he's OK. But with babies/toddlers, he tenses up, and if a child should make an unexpected noise, he becomes very scared: crying hysterically, trembling. Even small children making "happy noises" terrify him. He also can't tolerate them invading his personal space--e.g., cries if another kid comes near him while playing. We did start playgroup when he was 6 months old. It was fine at first, but maybe he was frightened by some unknown incident? Now we've reduced his major peer activities to music class, where there is no one-on-one playing. We have received so many conflicting pieces of advice from people. Some say he's manipulating us, but my instinct tells me "no." Even after a bad experience (e.g., he cried for an hour at a friend's house yesterday because of her 2-year-old's noises), he speaks positively about it, and is not upset about going anywhere even when he knows there may be kids there. How to handle all this? We try to comfort but not over-comfort. Expose him more? But if it ends badly every time, does it just reinforce his fears? (Two more notes: he's getting a sibling in 4 months and he did recently play near a quiet toddler for 5 minutes but melted down when she started to cry.)