What book? I am not a fan of speculation masquerading as science, and can recognize unsupported conclusions, even outside my own field. Very little has been established regarding gender, beyond some aspects of physiology that are relatively straightfoward to measure. The most sound conclusions are at best statistical, meaning they say little on an individual level, which is most of us experience life. When people and institutions stop asking about gender and stop making decisions, exclusions, and requirements based on that, beyond matters of personal preference, gender will no longer of concern. Until then, disregard of it and its use as a pretext for how people are treated is just unilateral disarmament.
Bottom line: if gender and sexuality should be a complete nonissue outside of personal relationships, and I think it should be, everyone needs to be on board with that, and act accordingly.
Blueprint: The Evolutionary Origins of a Good Society: Nicholas A. Christakis: 9780316230032: Amazon.com: Books
In the book it is shown that the only antidote to dictatorships or totalitarianism is the family unit. The stronger the family unit is, the less loyal a citizen is to the state. In fact, statistically speaking, it is shown in the book that monarchies, and other societies which involved strong central forces of power which comitted atrocities did so by eroding the family unit and that the energy spectrum between the family and the government is diametrically opposed and a zero sum game - mathematically proven in the book.
There are several ways to reach the same conclusion and traversing one path creates a dominoe affect where all others occur. Changing gender is one leverage point which could result in the others falling depending on the threshold.
I know it's a hard pill to swallow but the difference between us and Nazi germany is the strong family unit. Socities are 99.9 percent similar. We notice the variation but rest assured, there is a blueprint.
By changing the relationships between lovers, to disintegrate the the family unit, totalitarianism is established or moved towards. Two methods in the book are limiting or saturating gender, or limited or overstating sexuality.
By doing so, the one on one relationships required for the family unit disintegrate, and the state acquires enough power to enslave the citizens.
Book was written by a liberal.
The idea that anything is a personal issue, and does not affect society as a whole is simply not true, however. Even moving a rock, or casting a stone on the water has rippling affects. Outside of the system the affects are exponentiation. But that is only based on our observation. We still do not know if there are analogous butterfly affects operating on the level of the quantum, and then finding their way into the spectrum of our own observation capabilities.
Creating polyamory for instance destroys the one on one bond required for family unites to form, thereby killing the species, in the long run. This is why poly-amorous societies as a rule disintegrate into totalitarianism - statistically speaking such an outcome in history is always guaranteed.
That being said, being meta-modern, I woulnd't personally want someone to not have a right to declare themselves as they wish, even if it is going to result in the demise of humanity. But that is because I have been programmed to be liberal.