Each package contains a minimum of 25 seeds. When you plant seeds there is no guarantee as to how many female plants and how many male plants will result. One hopes that it is at least a 50:50 split.
Only the females will produce fruit. The males are necessary for pollination. In reality, no more than 1 male is necessary for the pollination of 8 females. However, the leaves of all the plants provide an immunity boost when served as an infusion (we call it 'tea', but technically, it is not).
Please note that seabuckthorn plants sucker, so you will end up with much more plants than you begin with.