Relevant to the topic of personality and choice in the article. Robert Plomin in his book Blueprint cites the pretty astonishing finding that the weight of adopted children is pretty much not at all correlated to the weight of the adopted parents, whereas the weight of the birth parents is a strong indicator for weight in adulthood, even if separated at birth.
Is that surprising? Weight is strongly correlated with height, which is absolutely genetic. I'm sure that BMI would be less correlated than pure weight, although I don't know by how much.
https://imgur.com/XIyvzFz