How can siblings be raised the same but turn out totally different?

[stopdiggin]

5. interesting.

https://developingchild.harvard.edu/resources/what-is-epigenetics-and-how-does-it-relate-to-child-development/

Although - most of the definitions/explanations I ran across in a quick search, concentrated on environment influencing 'expression' in genes - which still leaves something of a question mark around variations in identical twins? Which, unless separated, would seem to be very close in external influence (one supposes), at least through early development. I'm probably not getting in deep enough.