Rbp61/Rbp63 mutants are fertile. The number of germ cells in the males of this genotype is the same as in wild-type. No abnormalities are found in the number of germ cells present in germline cysts either. The only defect observed is the occasional mislocalisation of the somatic hub in 5 out of 20 testes analyzed. In each of these cases, a rosette of stem cells is observed around the irregularly localized hub cells, indicating that while the hub is no longer attached to the basal lamina, no loss of stem cells is ever observed.