What decides the stats of your pokemon when they hatch?

Question

I looked at 5 gible eggs all from the same mom two male three female one male was dominant the others were weaker so ?

Answer 1

It is completely random unless you use the everstone to increase the odds of haveing the same nature as your pokemon that holds it. The power items that increase evs can also determine if it is held by one of the pokemon will make the offspring inherit 2 Ivs to the corresponding power item

Answer 2

I believe that it depends on the pokemon's nature for how it grows, like a pokemon with the Hasty nature will have different stats then the same exact pokemon with a Quirky nature. If you're talking about them all at level 1 then I can't really help there.