The ORIGINAL Bradford pear, of which I planted ten nearly thirty years ago, was/is sterile. The tiny fruit does not produce viable seeds. However, its round full canopy caught too much wind for its brittle branches to withstand and it quite often split nearly down the middle in a storm. So, an "improved" Bradford Pear was developed and the "Cleveland" cultivar was introduced.
It was more "football" shaped so as not to catch so much wind. But, it is still brittle and breaks nearly as often. AND, they not only are not sterile, they reproduce like rabbits! Carried by birds, squirrels and other critters, they spread into flower beds, fence lines or out into the surrounding community. Did I mention that they have "spurs"?
Spurs may not be true thorns, but they are awfully similar and will impale the careless hand that carelessly tries to pull the sprouts out of the ground. The Cleveland has been considered an invasive species in Illinois for several years. I will be years getting rid of the "children" of the ones I bought to replace the original Bradfords.