Here is a comment that I found interesting. Q(junior) is of the opinion that the Q did not reproduce because they were uncertain what they would create. Is it possible that the "child" of two Q is stronger than a "original" Q?
It's an interesting idea to consider, and since the Q don't reproduce in the same manner that humans do we can look at other possibilities. Instead of q receiving half of his "Q-ness" from his mother and half from his father (which would result in him having the same amount of power as his parents) he could have more if the full potential of his parents was passed on to him.
I think of it like this:
a) half from each parent (let x represent the Q's power):
1/2x + 1/2x = x
So q ends up with the same amount of power as each of his parents.
b) full potential of each parent:
x + x = 2x
But in this case he would have twice his parents' power.
It would probably be far more complicated than this since the Q do not operate on finite principles like we do. Also, I am by no means an expert in genetics or exobiology, so this is just my hypothesis.