I believe the answer to this is partly yes and no. The problem we've made over the ages is equating physical strength with superiority. If we look at the sexes not in terms of linear strength but as highly specialized tools designed to ensure our maximum chances of survival, then the motion of superiority/inferiority becomes completely moot.
We are each designed to best fullfil our role in the complicated equation of survival. The sexes are neither superior, equal nor inferior to each other, they're simply differently outfitted. Many common tasks seem easily within the grasp of both sexes, however certain roles are best fulfilled by one sex or the other. This doesn't establish supriority, rather it compliments the abilities and strengths of the other.
Men seem to be particularly adapted for hunting prowess and providing protection. We are more muscular, we are able to withstand more physical exertion, our ability to perceive three-dimensional depth and navigate are more highly developed, our ability to crunch numbers also seem to be more developed, and our main sexual hormone testosterone provides higher levels of agression.
Women, on the other hand, seem superbly adapted to the reproduction and rearing of children. Their bodies, while not as muscular, seem to be able to withstand more stress than a man's, their sense of hearing and communication are more highly developed, their ability of facial recognition and certain cognitive functions are more developed, and their ability to concieve, along with all the complicated hormonal and immunological systems, work in concert to provide the perfect environment of protection for her child, both before AND after birth (i.e. breastfeeding). This sytem is so complexed that it's still not fully understood.
Instead of competing on the basis of perceived physical strengths, both sexes should accept their strengths and weaknesses and work together to compliment each other. This makes us stronger as a species, and it is only through such means can we continue on to the next step in our ongoing evolution.