Is there a selective rural-urban migration in respect to height and weight?

Height and weight were examined in rural-urban premigrants from heavily depopulating regions in the countryside. The analysis involved children, 5.75-8.74 years, from rural schools in two rural districts in Poland, Bystrzyca Kłodzka and Pińczów, in 1978. Migrants were identified while reexamining the children in the same schools 10 years later, i.e., in 1988, and by using information from local census registers. The premigrants from the villages of Kłodzka Pińczów and Pinczow districts do not differ in height and weight when compared to the total population of rural children examined in each district. The comparison of height and weight in premigrants and nonmigrants in groups homogeneous for SES of the children's families indicates that if the SES of rural families is very low, individuals smaller in size tend to remain in the rural areas. When SES of the rural population improves, migration of the young seems to be random in respect to height and weight.