Be sure to check out this insightful article at Kidscreen.com about Hot Wheels World Race, and the process of making that property a success.
"a few Mattel execs (who are no longer at the company) expressed hesitation about female characters. They didn’t know how young boys would respond to them, Hot Wheels being a very “boy world” and they thought perhaps we could do without them. This would be one of the few times I really spoke up. I really wasn’t interested in a major story world that didn’t include girls. Had Disney’s Fairies property not included boys I would have protested equally loud. Single gender worlds compound artifice and by definition are not resonant with the contemporary world in which we live. It’s one thing to market toys to boys, but it’s another altogether to create entertainment in which girls don’t exist.
Fortunately, the series animation house Mainframe and several others at Mattel did agree with me and female driver Lani Tam got some nice screen time. There would be several other heroic girl drivers who would star in their own comics as well. Bravo Mattel!"