In my opinion I believe Quina to be asexual--neither male nor female. As no "female" Qu's were introduced in the game. Also--and correct me if I'm wrong--I don't remember Quina ever mentioning its parents.

As Qu's are native to swamps, it is my belief that they lay some sort of egg, as the majority of swamp-dwelling creatures do. Also, as far as a form of "mating" goes, evidence--not proof--lies in their affinity for eating. As the body's most basic needs include sex, eating, and shelter it would make sense for eating to become more favored if one could not mate. Like mating and exercise, eating causes the body to release into its system endorphens and other pharamones and chemicles which produce positive and euphoric feelings...which is why people binge when under stress or depression.

But then again, maybe I'm just over-analyzing.

Kupo!