What causes developmental delays?

Many factors: Developmental delays often just are without much possible explanation. Other times there can be predisposition because of genetics, prematurity, toxin exposure, intrauterine problems, and disease/illness. Interactions with your child of all kinds help development.

Eye of beholder: We have developed expectations of when children should develop skills. Gross motor, fine motor, social, and verbal skills develop at different rates. Each child will develop these skills at their own rate. If they are significantly slower than expected, then they are delayed. It is appropriate for the pediatrician to offer therapy and assistance and to look for causes, and to offer specialist.

Breaking it down: Genetics, biology, & environment, called genotype, phenotype & environtype, interact to cause difficulties in development/academics, behavior & peer interaction. That's why developmental//behavioral pediatrics, a cognitve subspecialty, uses a biopsychosocial model; i.e., we need reliable information about all 3 in order to answer parents' "why, how & when" , as well as, "now, what do we do?".