Used as a spice, the berries (not true berries, by the way) from Juniperus communis are edible, while berries from Juniperus drupacea, Juniperus oxycedrus, Juniperus phoenicea, Juniperus deppeana, and Juniperus californica. Some species, for example Juniperus sabina, are toxic and consumption is inadvisable. (Source: Mountain Herbs)
Male and female flowers are borne on separate plants, so you must have both if you want berries....