Why does my child cry when he sees or is near a child of about the same age?

My baby is 21 months old. He starts crying when he sees or is near a child of about the same age. He has just started acting this way and he doesn't do it when he sees younger children. He spends a lot of time with me, his mother, at home. Why is he behaving like this?

What a fascinating observation! Do you think he is so aware of a baby his own age because he wants to imitate him, be like him and get close to him, or cry out for his attention? This is an age when toddlers need each other and they learn a lot about other children when playing together. A 2-year-old learns a great deal by interacting socially with his peers. It would take him much longer to learn the same social mores on his own. It doesn't sound as if your child has regular playtime with children his own age. Arrange some playtime with another toddler whose temperament is similar to your son's. Adjustments can be tough for a child who's never spent a significant amount of time away from home. Understanding your child's need for extra hugs and kisses while he's gets into the swing of peer-group life will help make the adjustment easier and smoother.