Cannabis seeds packs are separated to two categories.
Mixed: Male and Female seeds.Feminized Marijuana Seeds: Only female seeds.
Fact: Male plants are useless, unless you want seeds in your buds. And you don't want seeds in your buds because you can't smoke them.
Therefore feminized seed usually cost more, but worth the extra cash if you know what you're doing. If you know what you're doing, feminized marijuana seeds save you a lot of hassle.
Good luck with your growing!