We are all born equal, the differences being cancelled out by the unique qualities which are built-in by The Almighty. "Born" is a significant word in the indent. As we grow, this equality starts see-sawing, in the favour of those who use their "unique qualities" for their better, against those who either don't know how to use them.
All the differences are our own created. People consider themselves superior due to social differences, main difference that is created between the ignorant and the learned. No one would assign major responsibilities that are crucial to the community to an ignorant person.
Like most of the main religions, Islam teaches that in the sight of Allah Almighty, all people are equal, but they are not necessarily identical. May Allah give us all enough physical and mental strength, so that we, one day, could count us in the formers. Ameen