My son is my step son, but I've been with him and the Lady F since he was 1 1/2 years of age. In other words, I was the one there to nurture him the whole distance while contributing nothing to what nature handed him.
You can see that we do not look alike. My voice is kind of reedy and not very deep, while my boy's voice makes Ramana and his sonorous baritone sound like a Vienna Choir Boy. He is taller than I am. And I'm about as far as I'm willing to go with physical comparison, LOL!!!
We knew the physical would have little resemblance unless by chance. The interesting part is to compare the behavioral traits, because that is potentially affected by both genetics and experience. Since I was always the dad in his life and since he never spent any appreciable amount of time around his biological family (even though we are close to them), you would expect him to behave somewhat like me, modeled after my behavior.
Well, he is 33 now, so the results are pretty much ready to be tabulated. And the answer speaks strongly in different ways for both sides. His values are pretty consistent with mine, his sense of right and wrong, but he has mannerisms, skills and likes much more consistent with his biological family. He doesn't think like me even if we are very close. My daughter, who is my biological heir, does think like me in many ways that immediately jump to my attention.
Biology is a very powerful influence and it has amazed both my wife and me how much is obviously biological that we would never have suspected. It is very clear that my son is an inheritor of his biological family. I've got to tell you, though, that the combination sure seemed to work magic. He is a great father, a sensitive man and ... one helluva plumber and construction boss! Really!