Feminized cannabis seeds are genetically modified to produce only female plants. Usually, a cannabis seed will produce a male or female plant; the entire process is determined by the X and Y chromosomes. A plant with two X chromosomes will be female 99.99% of the time, while a cannabis plant with X and Y chromosomes will almost always become a male plant.
The advantage to feminized seeds is that the plants will be female 99.99% of the time. Female cannabis produces a much higher content of active principles like THC, CBD and CBN compared to male plants.
Before being officially launched on the market, all seeds are tested and grown with extreme care to ensure that plants are genetically stable and consistent.