Assigning probabilities to alleged relationships, given DNA profiles, requires, among other things, calculation of a likelihood ratio (LR). Such calculations usually assume independence of genes: this assumption is not appropriate when the tested individuals share recent ancestry due to population substructure. Adjusted LR formulae, incorporating the coancestry coefficient F-ST, are presented here fur various two-person relationships, and the issue of mutations in parentage testing is also addressed, (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.