In the end, studies like these are meaningless when a city (NYC) can propose a law allowing people to decide for themselves what gender they are. And if you can decide what gender you are, which is determined at birth, then I guess you can decide what race you are and what color your eyes and hair are as well. It's all up to you and has nothing to do with reality.
That can make getting a driver's license and other daily activities (like choosing what restroom you should use) a bit tricky, I'd think, but so what? We're in the Age of Liberal Enlightenment.
I just decided that I am black.
Now I can enjoy the benefits of affirmative action and all the other race-based govt. discrimination.