Not that obscure, but most orange cats are male since the orange gene is tied to the x-chromosom, so male cats only need one copy to appear orange. Female cats have to have the orange gene on both x-chromosom to be fully orange.

And usually only female cats can be calico/tortoise since the orange gene is co-dominant, so if they only have one copy of the orange gene both the orange and black will be visible.

A seemingly male calico/tortoise cat is usually intersex and sterile.