A colleague met my sons, Christian and Jan. He said, both got my mannerisms and sounded just like me. But, he said, they are more good-looking than me. I threw him out of my flat ha ha!!! That was meant to be a joke!
Well in spite of the importance of heredity, no child is a carbon copy of the parents. Brothers and sisters often do not have the same eye or hair color because they may inherit these characteristics from different sides of the family. Many ancestors contribute characteristics in each newborn baby, and these sometimes skip a generation or two before showing up in family resemblances. A tall youngster whose parents are short may be a "throwback" to a grandparent or great-grandparent who was tall.

Rani Marri, Riza Marie, and Rina Marri
On a side note, I bonded a long time with my twin grand-daughters, but it didn't help me at all to distinguish who is who between the two. I wonder why? May be, I am not trying hard enough to recognize even the slightest difference between the two. Calling them by their names offered a little help.