ROFL, you just shot everyone in the foot that believed that genetics are the stepping stone through life.
if they are twins a big god damn portion of their genes are the same (or very close). Mom liked Tommy more than Joey… Dad liked Joey more than Tommy. Mom and Dad split up and Mom got custody of the kids. Tommy continues on with life, and Joey misses the support his Dad used to give him. See where I am going with this. influence is everywhere. Its in the eyes of the beholder.
one example.