Motor Development and Season of Birth in the First Two Years of Life

This paper analyzes the connection between the season of birth (spring, summer, autumn, winter) and the achievement of 18 elementary motor development steps (milestones) in the first two years of life. The relationship between the month of birth and child development has long been the subject of hypotheses and studies. Previous studies have shown that relationships exist between the month or season of birth and the development of various physical factors, disease risks, behavioral traits, and emotional development. Studies that ex- amined the effect of season on motor development in infants indicate that those born in winter or spring have the best conditions for development. These results suggest that experiential factors, associated with seasonality and variation in climate affect the timing of acquisition of motor milestones. The data come from an ongoing research project in which more than 3200 parents living in Germany are taking part. Using a "citizen-science approach," parents report their children's developmental progress online using a calendar that charts 18 motor skills from birth to the point when children manage to walk on their own (around 14 months of age). Longitudinal data for motor milestones from more than 560 children are currently available.