Final answer:
The presence of specific receptors on target cells determines the specific targets of hematopoietic growth factors.
Step-by-step explanation:
The property that primarily determines the specific targets of hematopoietic growth factors is the presence of specific receptors on the surface of target cells.
Each hematopoietic growth factor binds to a specific receptor on the target cell, triggering a series of signaling events that lead to cellular differentiation and proliferation. For example, erythropoietin binds to the erythropoietin receptor on erythroid progenitor cells, while colony-stimulating factors bind to specific receptors on myeloid progenitor cells.
Overall, the specificity of hematopoietic growth factors for their target cells is determined by the specific receptor-ligand interactions.