[Growth, maturation and environment]

Using as example the secular trend, relations between growth, maturation and environment are discussed. This phenomenon is characterized by an increase of the average height and an acceleration of growth velocity and maturation. The increase is acquired mainly in the early childhood. The secular trend has been modified by local and socio-economic differences in the frequency of malnutrition and morbidity. It is now minimal in countries with high standards of health and hygiene. It can appear or can be accelerated in all developing countries with progress in child-health, especially in early childhood. A negative trend can be expected in every country, where child-health deteriorates for a long time.