According to the premier register of thoroughbred horses in the U.S., all of the horses are between four and seven generations of Secretariat.

In fact, a search of pedigrees shows every horse running in the 151st Kentucky Derby is a descendant of Secretariat. While it sounds impressive, more often than not, if you go back six generations in most horses, you'll find they're a descendant of some great, like Secretariat or Northern Dancer.