The presence, size and location of an asteroid belt may determine if life can evolve on an Earth-like planet. If this is the case, less than 4% of the observed solar systems may have the potential for life.
Astronomers studied archival information of debris disks and large planets around stars, as well as theoretic models of asteroid belt formation. They concluded that the creation of an asteroid belt similar to the one in our solar system requires a Jupiter-sized planet in the right position, as well as enough debris.
This combination appears to be rare, and suggests our solar system is special.