Sex determination..

This is something new...at least for me.

Besides having XY sex-determination system, we do have other system - ZW sex-determination system.

Unlike XY system, gender is defined through its ovum. Which means, the female. Ok, so far, none of the web said this system determine mammals' gender [which includes us; homo sapien]. It determines the sex of offspring in birds, some fish, and some insects (including butterflies and moths), and some reptiles, including Komodo dragons. Huh? No wonder female comodo is more dominant...hohoho

While XX [homogametic] means female, XY [heterogametic] means male, in this system ZZ [homogametic] defines male and ZW [heterogametic] defines female. Could you see the reciprocation? the contradiction? Hehehehe...