Oryx was a female and over time became male. This implies their race was similar to how frogs and certain species of fish can chemically change sex based on circumstances: [quote]In most species of sex-changing fish, the males are the alpha sex, meaning the males are larger and more aggressive and usually do very little if any tending of the eggs. In these species, fish start out as female when they are small and then change sex into males when they get large enough or tough enough to establish behavioral dominance over the other fish in their group. [/quote]