This feels like floating point would not work well.

(Context for the non-programmer-socks crowd) Some systems store decimal numbers in a way that precludes an exact representation of some vslues. So 1/10 might have be stored as 0.0999999999999976, which makes little difference until the inaccuracy gets multiplied and rippled around enough to generate a letter for being 0.0000000047 cents overdrawn.

I suppose for gender, the rounding error is catgirl. we're all ever so slightly willing to mew and swat away people trying to rub our bellies, it's just a matter of when it shows up in an unexpecyed place.