"Shulamith Firestone (born January 7, 1945), (also called Shulie, or Shuloma) is a Jewish, Canadian-born feminist. She was a central figure in the early development of radical feminism, having been a founding member of the New York Radical Women, Redstockings, and New York Radical Feminists. In 1970, she authored The Dialectic of Sex: The Case for Feminist Revolution, an important and widely influential feminist text."
Shulamith Firestone was basically a pioneer in postgenderist philosophy and popular feminists like her
Joanna Russ was another second wave feminist icon who promoted postgenderist ideas in her novel titled "The Female Man", the novel written in 1970 depicts a future where all men have been wiped out by a gender specific plague and where women are all lesbians, have genetically engineered each other to be super intelligent and have invented artificial wombs to enable them to reproduce without men. It also depicts another world where males turn all the boys into transvestites using cosmetic surgery in order to fulfill sexual desires. In this world there is also a perpetual war between the men and women.
The Female Man includes several fictional worlds.
Joanna's World: Joanna exists in a world that similar to Earth in the 1970s.
Jeannine's World: Jeannine lives in a world where the Great Depression never ended. The Second World War never happened because Adolf Hitler was assassinated in 1936, and Chiang Kai-Shek controls Hong Kong, as Japanese imperialism still dominates the Chinese mainland.
Whileaway (Janet's World): Whileaway is a utopian society in the far future where all the men died from a gender-specific plague over 800 years ago. After mastering parthenogenesis, women form lesbian relationships and parent children within them. Although the world is technologically advanced, their societies are mostly agrarian. Their technology enables them to genetically merge ova in order to procreate. Joanna Russ's Nebula Award winning short story When It Changed (1972) also takes place on Whileaway, but earlier.
Jael's World: Jael's world is a dystopia where men and women are literally engaged in a "battle of the sexes". Although they have been in conflict for over 40 years, the two societies still participate in trade with each other. Women trade children in exchange for resources. In order for men to cope with their sexual desires, young boys undergo cosmetic surgery that physically changes their appearance so that they look like women. Jael is heterosexual and has sex with Davey, a lobotomised adolescent male, at her home."
High profile figures like Marilyn Manson have also promoted postgenderism;
"Another high profile of covert postgender propaganda is seen in Marilyn Manson's 1996 album "Mechanical Animals." The seventh track is entitled "Posthuman", and the cover shows Manson as the sexually ambiguous character Omega. Omega of course refers to the end, in this case the end of humanity as we know it, but the beginning of posthumanity."