I am having problem using the word "sex" and "kind". Sex can be a general term for the different genders between Male and Females. While Sex can also refer to the action between a man and a woman in the creation of a new living creature. I find this abit tricky because if I use the word wrong I can find my self around a bunch of gigilling people. So I choose to use the word gender more than the sex. Kind can describe the characters. While species is more proper term to use when describeing different animals. Since the word species can determine if it is a pony, unicorn, and pegasus. Or it can describe a Zebra, Bison and Mule. Since these are different species the only exception is that a Pony and Zebra belong to the same family which is Horses. So it is all up to the user for you to decide.