Bizarre Alien Sexes: While the eldrae started out with the standard two (male, female), biotechnology has since added two more to their repertoire (neuter, hermaphrodite). And the standard taxonomy of sexes in their language, which has to cope with other species, includes two more – the most common mappings of other-species sexuality (prenuptial catalyst, postnuptial catalyst). And the language allows for an arbitrary number of other gender affices, because while most species can fit into that six-gender system, usually having no more than four and the mode being two, the one-to-couple-of-dozen-variants spread in how species divide into sexes means that… well. Yeah.