What is the Purpose of the Study?
The purpose of this study is to investigate whether fetal growth is related to infant growth, and especially the body composition of infants. We are interested in whether this growth is influenced by genes or the environment, or both. The best way to do this is to look at whether foetal and infant growth is the same or different in identical (monozygotic) and non-identical (dizygotic) twins. Since identical twins are genetically identical, any differences between them must be caused by environmental factors. Non-identical (fraternal or dizygotic) twins share only half their genes in common so differences between them can be due to the genes that they donít share or the environment.