O come now. Everyone forgets sometimes. Anyhow, Charles, do you remember Yoshie arguing that in a post-capitalist culture there would be one sex and many genders? If anyone wants Gould's review of Laqueur post me off-list and I'll send it to you.
^^^^
CB: Sexual reproduction originated billion years ago ,or two. First earth lifeforms reproduced by cloning. Gould calls origin of sex a rev in _Ever Since Darwin_. Selected for because with inheritance from two different individual organisms,it increased variety of offspring, which enhances adaptability to changes in the environment.
Sexual reproduction _must_ have two different sexes , by definition. Intercourse between same sexes is not potentially fertile. Sex is defined as ability to have fertile intercourse with the opposite sex. So, notion of one sex doesn't make sense.