Abstract
The differences existing among some european longitudinal growth studies make it necessary to be cautious in the use of standards constructed on different populations. The improvement of the environmental conditions during the last 20 years is probably the most important cause of the "catch-up" phenomenon of the spanish stature. It is probable that racial characteristics also play a role, even in the same country as can be appreciated on comparing two spanish longitudinal studies based on children originary from different regions. All of wich indicates the need to use own standards in those countries wich, like ours, have lived through a period of intenses changes. Even exploratory studies of regional differences in the same country seem necesary.
