 Among his progeny was Oedipus, the 1950 and 1951 American steeplechase champion.Blue Larkspur made the broodmare sires list every year from 1944 through 1960, with his daughters producing 114 stakes winners and six champions.This may be because he is thought to have been a carrier of the X factor, a genetic trait which causes an extraordinarily large heart, and is only passed on to a stallion's daughters via the x-chromosome, although the basis of this theory has not been scientifically proven and dismissed in scientific circles.