An unusually beautiful graph showing how important genetics can be in various life domains. http://www.nature.com/articles/s41539-017-0005-6/figures/1 … via @slatestarcodexpic.twitter.com/2lvRhzk2qa
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Yes, these are some of the zillion things people have checked. Your article ignores the research. See eg https://www.ncbi.nlm.nih.gov/pubmed/26410687
Re equal environments assumption, tested in eg http://www.nber.org/papers/w16711 , http://sociology.as.nyu.edu/docs/IO/41018/twins_BG.pdf … , etc, a zillion others
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.