Infant milestones can be a source both of pride and anxiety for a new parent. Baby's firsts – first tooth, first steps, first word – are moments of joy that many parents immediately compare with ...

Crawling, the first word, the first steps — these are just a few of the key milestones in early childhood development that parents eagerly await as their child grows up. However, there are other ...

This piece is part of Scientific American's column The Science of Parenting. For more, go here. One study of children with achondroplasia found that 100 percent of them commando crawled when they ...