If both my parents have been given some type of general anesthesia should i be worried about maligant hyperthermia ?

No: Just because one has general anesthesia does not mean they are more prone to developing malignant hyperthermia. If your parents got malignant hyperthermia then there may be concern....

Not really,: MH it is a rare, potentially fatal, inherited disorder of the skeletal muscle, associated with general anesthesia. Dantrolene sodium is the drug of choice during the crisis. For your information, testing for MH-susceptibility is available today. This is very important in individuals who experienced a MH crisis as well as in close relatives of affected people. Talk to your anesthesiologist.