well, I see it as a nice effect. Perhaps certain cards have a set gender, and all other cards get a random gener when cast (creatures) and others have a gender of (null)
then you get cards like
Creature Ability: Charm
target creature of opposite gender joins your team
Dance Macabre/Allegro/Vitali
Some spell that caues creatures of the opposite gender to pair up and do something (deal damage to each other, make a mutant offspring, gain Adrenaline, etc)
Seduction: Target creature gains the Ability Charm
Honorable Code:
Target creature may not target or damage creatures of the opposite gender (null is ok)
so, just some ideas. Should fully be implemented. Opens a wealth of opportunity, with Nymphs being female of course, crusaders male, most creatures being random and skeletons, cells and Armagio being null.