From routine appointments to emergency services, it's important to get the care you need-when you need it. But we understand you may be delaying your health needs over concerns about safety. At Mount Sinai, our doctors, nurses, and staff members are working continuously to ensure your safety so that you don't have to put your health on hold. All children master a series of developmental milestones, such as playing peek-a-boo, growing teeth, and learning to recognize their own names. The exact timing of these milestones varies from child to child. Some children advance more quickly with their social skills, for instance, than motor skills. But there are general ranges of what is considered ‘normal’ development.