Zzyym's parents and doctors attempted to 'fix' them via multiple surgeries during childhood. There is no way to tell now what Zzyym's reproductive abilities might have been had they been allowed to develop naturally. They might even have been one of the rare intersex people who could produce both types of gametes.
Also, I think it's important to note that some people are completely unable to produce gametes. If we use gamete production as the standard for sex designations, they would be considered sexless.
For the bazillionth time...
1) The gamete that a body is arranged to produce is what determines sex, regardless of whether they actually do produce that gamete or not. Sterility does not make a person sexless. If they are a sterile person with testes, they are male. If they are a sterile person with ovaries, they are female.
2) I think there's been one single documented case of a human who produced both eggs and sperm, and that person did NOT have a DSD, that person was a mosaic - literally multiple people in one. People with DSDs cannot produce both functional eggs and functional sperm
at the same time. The level of testosterone needed to produce sperm will also destroy eggs; testosterone low enough to allow viable egg release is too low to generate sperm.