Analysis of Covariance

Hi everyone,

I would like to ask a question about the type of scale (e.g. categorical , continues variable) that should be use as a covariate.
I have to ethnic groups -both gender- and I want to examine differences between groups in cultural scales controlling for gender, is that write to use gender as a covariate if this is categorical variable not continues.
Or is there any reason could prevent using gender as covariate!

One question more:

If there is a huge difference between groups in mean (let’s say group 1 = 50, group 2 = 18) is that possible or not? And what can make this big difference?
E.g. participate scores? Groups seize?

Thanks All