"when they say height is mostly genetic ... under current social conditions" This is always what's meant. Perhaps it should be said more often... but nobody do

"when they say height is mostly genetic ... under current social conditions" This is always what's meant. Perhaps it should be said more often... but nobody doubts that we can grow a bonsai. The interesting question is how much do different factors matter in our present environment (and again ideally one should specify, e.g. rich-country & above-poverty-line, not just 201X) and in environments we might reasonably hope to create.