Coincidentally, I'm in the middle of reading "The Neuroscience of You" by Chantel Prat. The author's comments on twin studies:<p>> some characteristics that have genetic influences, like extraversion, also influence the kinds of environments and experiences people will seek out. And other genetic factors, likes how tall or attractive you are, can influence your experiences by shaping the way others treat you. To further muddy the nature-versus-nurture waters, the rapidly evolving field of epigenetics is showing that environmental experiences can create chemical changes in our DNA!"<p>> To figure out how surprising the similarities between long-lost twins (or triplets) might be, we've got to ask the question, "How likely is it that any two random strangers who meet on the street would also be similar in this way?"