The present study investigates the influence of the presence of same-sex litter-mates on the attainment of breeding status by subadult Townsend's voles in natural populations. Males and females were less likely to disappear from their natal area (disperse) and more likely to delay sexual maturation if they had at least one live same-sex litter-mate within the natal home-range when reaching adolescence. Furthermore, among male and female sexually mature subadult voles, the probability of persisting near the natal area and hence recruiting as a breeding resident was higher for those individuals that had a same-sex litter male in their vicinity when maturing sexually. A removal experiment suggested that the increased probability of recruitment of members of family groups was not caused by intrinsic differences between offspring from different litters but results from social interactions between same-sex litter-mates. Dispersal tendency by subadult voles is therefore a highly flexible trait which is influenced by the social environment experienced by individuals.