A photo of a group of mothers together with their infants, a time when moms often compare their children's milestones...
Groups of parents often compare their children's milestones...
Photo (c) En Tien Ou
Parents are often discouraged from comparing the growth and development of their own child against that of other children. The reason is that there is a wide range for when children reach most milestones. For example, most children begin to walk well on their own sometime between 11 and 15 months. If you have a group of 12 month olds, you will likely see some walking well already, and many others still just cruising around while holding on to things. And all can be developing normally.
And even beyond the wide range of normal development, there are always those early bloomers and late bloomers who are also developing normally, too.
If your child isn't reaching his developmental milestones on time though, it would be good to talk to your pediatrician to see if there might be a problem with his development and any kind of developmental delay.
Take that group of 12 month olds again. If you notice that they are all either cruising or walking, but your child still isn't even pulling up to a standing position, then he likely is delayed. Talking to your pediatrician would be a good next step in evaluating his development.