I think that you're refering to SEXES, not GENDERS. I'll show you what I mean.
So there is a difference between genders and sexes, and since you haven't figured that obvious difference apart, I'll have to explain it to you... So a sex is the "gender" that you're assigned to as a newborn, whether it's male, female, or in rare cases intersex. A gender is something that everyone can change if we wanted to. That's were the terms 'transGENDER,' 'GENDER-fluid,' 'GENDERqueer,' etc. come in. It is not 'transSEX,' 'SEX-fluid,' 'SEXqueer,' because you can't change your sex, unless if done so by the choice of a parent and a specialized doctor, but that's not the point.
So basically saying, you are referring to 2 sexes, not 2 genders. Case closed!