The predominant view is that all children should have the same growth pattern below the age of 5y, independently of their ethnic origin. So all differences in growth should be related to living conditions, in particular to suboptimal nutrition. This view is based on the WHO growth study which showed that growth was very similar in healthy children in 6 different sites with different ethnic background. Similar studies in the 70’s already reached the same conclusion. The logic, however, has its limit. Even if you find no difference in n populations, this does not mean that the next (n+1) population will be the same. Recently, concern has been raised on the validity of weight-for-height in some populations as apparently it is influenced by leg length.(1) This seems to be a problem in pastoralist populations who have long legs and so will return low average weight-for-heights even if the food situation is not critical. The WHO study did not include any pastoralist population, so this is a concern. For a good discussion about factors influencing leg length, see a recent excellent review.(2) 1. Myatt M, Duffield A, Seal A, et al. (2009) The effect of body shape on weight-for-height and mid-upper arm circumference based case definitions of acute malnutrition in Ethiopian children. Ann. Hum. Biol. 36, 5-20. 2. Bogin B & Varela-Silva MI (2010) Leg length, body proportion, and health: a review with a note on beauty. Int J Environ Res Public Health 7, 1047-1075.