A horse's genetic potential (or GP) is the athletic talent of a horse. Genetic potential stays the same throughout the life of a horse and cannot be raised or lowered.
The genetic potential of a horse is visible from birth, as long as the horse is owned by a player or by Gisela. Only the stats of Foundation and Wildlife Park horses are hidden.
You can find the genetic potential in the tab "Genetics" on a horse's profile:
There are 10 GP stats in total and they can assume a value between 1 and 100.
If you are training your horse for competitions, certain GP stats will have an influence on performance in different disciplines. You will find the full list in the article about competitions.