This article describes the potential of the Longitudinal Study to analyse different ethnic groups by broad period of entry. This is illustrated with the use of one variable (childlessness), but could be the basis for further analytical work on other variables. Each group has a unique demographic profile, which is largely explained by its migration history. Migration influences important life course transitions. Differences between more established residents (present in 1981 and 1991) and less established residents (present in 1991 only) imply that generalisations for the entire ethnic group or future generations should not be made.