The love of my life has cerebral palsy?

okay so my love has minor cerebral palsy in both his legs. they're really not that bad...but today he told me he had to help his cousin move, i thought nothing of it. than i asked him why it was taking so long...(two full grown men should move a few house hold things rather quickly)...he said his cousin has cerebral palsy to, but in his arm...i did A LOT of research on cerebral palsy and i was SURE it was NOT hereditary...but they're in the same family and suffer from the same disorder. is it hereditary? or possible genetic? i'm scared because we plan on getting married and having children together. i need to no if this is a threat to my future children or not. no matter if it is or isn't we will be together i would just like to not be so much in the dark to the possibility. thanks:)