When dealing with humans, there are only two Biological genders
as defined by the presence or absence of the Y-Chromosome. If
the Y-Chromosome is not present, or through some process gets
totally deactivated, the human will appear and function as a
Female. XX = Female XY = Male XXY = Male (Klinefelter's
Syndrome) XYY = Male (Aneuploidy - Normal Functioning Males) XXX
= Female (Aneuploidy - Normal Functioning Females) X = Female
(Turner's Syndrome - Generally infertile, other issues) Y =
Fatal (The Y-Chromosome is drastically smaller than the
X-Chromosome, which contains many necessary genes) XXYY = Male
The list goes on, since there have been records of up to XXXXX.
If there is a Y-Chromosome present, the human born will be male.
However, that is not to say that a person cannot psychologically
identify as something else. It's also worth noting that the
majority of known species are asexual and do not have genders,
and that those which do have genders do not always follow the
same rules (Fruit Flies, for insta