Developmental milestones are the behavioral or physical skills that infants and children develop as they grow up. There are set periods as to when children achieve these milestones. For example, an infant can lift its head by 3 months, sit with support by 6 months and walk perfectly by 2 years of age. It is normal that not all children achieve developmental milestones at the same time. They accomplish these milestones at their own pace. Minor or temporary delays of milestones need not cause any alarm. If children display symptoms like failing to sit without support by the 9 months, have stiff arms and legs with limited movement, are unable to stand up even after 1 year of age are suspected with developmental milestone delay or simply Delayed Milestones. Any inordinate delay in language skills that include speech and understanding can also be considered for delayed milestones.