Your parents were right on the mark by giving you magnesium and calcium supplements for the leg cramps.
According to MedicineNet.com, " Low blood levels of either calcium or magnesium directly increase the excitability of both the nerve endings and the muscles they stimulate. This may be a predisposing factor for the spontaneous true cramps."
Cramps are seen in any circumstance that decreases the availability of calcium or magnesium in body fluids, such as taking diuretics or inadquate amounts of these two mineral in the diet.
Thanks for posting,