A Dutch research project found that identical twins were more similar than fraternal twins in giving up meat. This suggests that one’s genetic make-up may play a role in whether one is a vegetarian or not. The genetic effect became less influential in males than in females as they grew older.
Herzog, H. 2021 Genes may have a big influence on vegetarianism. A new study examined how nature and nurture affect decisions to give up meat. Psychology Today Nov 8 https://www.psychologytoday.com/us/blog/animals-and-us/202111/genes-may-have-big-influence-vegetarianism