Let's avoid talking about genders and go directly to chromosomes. It fits to the sciency theme of the game to begin with. People with atypical chromosomes are collateral damage.
XX: Typical female.
XY: Typical male.
XXX: Triple X syndrome (female with an extra X chromosome).
XXY: Klinefelter syndrome (male with an extra X chromosome).
XYY: XYY syndrome (male with an extra Y chromosome).
XO: Turner syndrome (female with only one X chromosome, missing the second sex chromosome).
XXXY: A rare variation of Klinefelter syndrome (male with two extra X chromosomes).
XXYY: Another rare variation of Klinefelter syndrome (male with an additional X and Y chromosome).
XXXX: Tetrasomy X (female with four X chromosomes).
XXXXY: A very rare variant of Klinefelter syndrome (male with three extra X chromosomes).
XXXXX: Pentasomy X (female with five X chromosomes).
Aaah, reading upon this topic, it's like totally much more complex than it initially seemed. Although it's just a game, no need to have 100% scientific accuracy, but it doesn't feel right. ToDo: think about it.
Let's avoid talking about genders and go directly to chromosomes. It fits to the sciency theme of the game to begin with. People with atypical chromosomes are collateral damage.