Blonde Hair

My students are an amalgam of ethnicities and cultures, most can create an avatar similar to their own appearance (Though this is not mandated, they choose to out of a desire to mirror their hero). A number of girls brought it to my attention (I had not even noticed after several years of running classcraft) that there was no blonde character option.

Is there a reason I can tell these students that they cannot have an avatar that looks like them? Surely recolouring a static image cannot take long.

I hope you can respond with an answer for them as I did not know what to say other than that I would ask.