"Women"
As a term, Butler argues that "women" has taken on negative connotations. Although it is literally the correct word (perhaps one of the only correct words), it still has negative associations, because of how frequently women are disparaged by that name. She notices that men typically make negative comments about women by saying "women," whereas the term "woman" has more noble associations. She looks forward to a world where gender doesn't imply any associations.
"Woman"
Instead of the negative associations of the word "women," Butler explains the positive, noble associations that are implied when the word "Woman" is used. In political discussions about women's rights, the term tends to be Woman. This word is often capitalized, because it refers to a proper group of people, and although the terms are technically interchangeable, the subtle implication is that the term Woman is used apologetically, in defense of women's rights.
Gender as a concept
In this book, gender is shown to be a social construct, not because it was invented by any specific people for any specific purpose, but because it literally is a construct in another sense. Butler explains that biological sex is clearly accounted for in nature, but gender is not accounted for in nature. This argument means that although biological differences exist in the human race, the gender roles that shape our lives are not self-explanatory. They could change, and in this case, she argues that they must change.
Power and gender
The idea that men are supposed to be in power and women are inherently not qualified had persisted for eons and eons before this book, and the fallacy is still believed by many people today. Butler shows that this idea has successfully deterred women from seeking power, and she explains that any legitimate difference between man and woman in terms of their ability to lead an organization or a nation is purely due to this mistaken belief, because it leaves women chronically unlikely to learn about power, but by educating women to become powerful, the hateful idea would be shown to be false.
The patriarchy
This book contains an influential argument about patriarchy. Butler says that in nature, patriarchies are hard to find, but in human society, they are nearly universal. This problem stems not from nature, but from society, from human culture and the way that men have systematically removed power from women that nature would have awarded them. She notices that women play leadership roles in other species of animal, so that the patriarchy is shown as a construct of human creation.