Sex differences in the canalization of child growth and development: An example of genetic regulation

In case of a disease or nutritional deficit, the growth curve may show deviations from the percentile it was depicting, and once damage is removed, a strong regulatory force tends to restore its path. Such phenomenon is known as catch-up growth and is an example of canalization of growth. Girls are more favored than boys because, when faced with the same damage, their growth (and also their psychomotor development) shows less deviation than that of boys. Such difference is also shown in a higher prevalence among boys of growth retardation in general and some developmental disorders, including autism spectrum disorder and cerebral palsy. Infant mortality is lower in girls at all ages and life expectancy is several years longer in women from all countries. The cause of such differences in favor of girls has a strong genetic component and is enriching for the interpretation of clinical and epidemiological studies.