[Niamh.]

Originally Posted by LeatherTrumpet

they dont have the same upbringing, that is why children differ greatly in character, it depends on the relationship of the parents at crucial stages of their development - this can change greatly from one year to the next and explains why siblings can be very different but be just 2 years apart

It may not be exactly the same but in most cases kids growing up in the same household with the same parents will have very similar upbringings.