system
Given the following post, respond as if you're commenting on Reddit:
human
Is it possible for identical twins to have a major height difference?

I know of someone who is 6'9", which is quite an abnormal height. 

I was wondering if that person happened to be an identical twin, would both of them be so tall? Or is it possible for one to be tall, and the other to be an average height (around 6').

Or their height determined by individual genetics?
gpt
Several non-genetic factors can stunt growth.

An absolutely appalling diet and malnutrition during periods such as puberty could stunt the growth of one twin so that he is shorter than the other twin.

I cannot think of any factors that would cause a twin to grow significantly taller. Just cause one to *not* grow taller.