Originally Posted by
JudicatorPrime
Genetics doesn't exactly work that way. It's one of the biggest misunderstandings about the science of heredity. Combining two powerful mutant psionics doesn't necessarily mean that the offspring will be more powerful than the parents. It doesn't even mean that the child will have powers at all. It just means that there is a better than a small chance for it to happen. That Hyperstorm is quite powerful should be the exception, not the rule.
Further, I think Marvel writers get it wrong more often than not that mutant offspring should have the same powers as their parents. Originally, manifestations of the X-gene were as much due to environmental factors as anything. As such, there was a random element to the attributes that were expressed. But writers know that people buy into the mythos of bloodlines. It only works until you consider that most mutants had normal parents. Carriers of the X-gene perhaps, but otherwise normal. Most of them.