Racing: Geniuses of the gene pool: The great and not-so-great lovers

Seven who made it

Sadler's Wells (Born; 1981. Sire: Northern Dancer. Dam: Fairy Bridge). Superb pedigree, not quite the best of his era as a runner, but won his share at the top level and was notably tough. His seven consecutive championships is a 20th-century record. Best progeny: Opera House, In The Wings, Salsabil.

Mr Prospector (1970, Raise A Native - Gold Digger). Best - but not the best - over sprint distances, but unsound. Started his stud career at a low price in unfashionable Florida, rose to become arguably the world's best active sire. Best progeny: Gulch, Conquistador Cielo, Ravinella.

Northern Dancer (1961, Nearctic - Natalma). Tiny, unfashionably bred, failed to make his $25,000 reserve at auction, but a top-class runner in the States and a phenomenon as a sire, founder of the most influential dynasty in history. Best progeny: Nijinsky, El Gran Senor, The Minstrel.

Mill Reef (1968, Never Bend - Milan Mill). Defeated twice in 14 runs, winner of Derby, Arc, King George. Saved for stud after breaking a leg, twice champion in a career in contrast to Brigadier Gerard, one of two horses to beat him. Best progeny: Shirley Heights, Reference Point, Acamas.

Hyperion (1930, Gainsborough - Selene). Small but perfectly formed, idle but talented. The best of his generation at three (Derby and St Leger), but well beaten in the Gold Cup at four. Champion sire six times.

Best progeny: Sun Chariot, Aureole, Owen Tudor.

Nearco (1935, Pharos - Nogara). Unbeaten in 14 races, emerged from native Italy to trounce best in Europe on his final appearance. Retired to stud in England, champion twice. Best progeny: Dante, Sayajirao, Nimbus.

St Simon (1881, Galopin - St Angela). By a very good stallion, the only decent produce of his dam. Unbeaten in nine races, but never tested by another high-class runner. A nonpareil among sires, champion nine times.

Best progeny: Diamond Jubilee, Persimmon, La Fleche.

Seven who did not

Cigar (1990, Palace Music - Solar Slew). A superlative athlete whose 16 consecutive wins, including a memorable inaugural Dubai World Cup, is a joint 20th-century record for a US-trained horse. Retired to stud after his owner turned down $30m from Japan, but proved infertile.

Ardross (1976, Run The Gantlet - Le Melody). Resolute and classy, but won two Gold Cups, and a stayer, however admirable, is too unfashionable to get the opportunities to succeed and was soon demoted to covering jumpers, an area where one of his best sons, Alderbrook, shone.

Secretariat (1970, Bold Ruler - Somethingroyal) The beau-ideal of a thoroughbred, a perfect racing machine. Won his Triple Crown, taking the Belmont Stakes by 31 lengths. Though fanciful to think he might reproduce himself, he was, Lady's Secret and Risen Star apart, a disappointing sire.

Brigadier Gerard (1968, Queen's Hussar - La Paiva). Beaten once in 18 races, with the looks and constitution to match his exceptional talent. A true champion on the track, but at stud most of his stock not only lacked class but guts as well, Light Cavalry being one exception.

Royal Palace (1964, Ballymoss - Crystal Palace). Bred in the purple, and lived up to it. The best of his generation for two seasons (2,000, Derby, Coronation Cup, King George) over middle distances, but got only one high-class runner, Dunfermline, and a hurdling champion, See You Then.

Aurelius (1958, Aureole - Niobe). Winner of nine races, including a St Leger and twice at Royal Ascot, but infertile. Returned to track as gelding and won five times over jumps and was second, though disqualified, in Champion Hurdle.

Ormonde (1883, Bend Or - Lily Agnes). One of the greatest racehorses in British history, unbeaten in 16 races against vintage opposition, including a Triple Crown. His stud career was compromised by illness and infertility, though he got one celebrity, Orme, before his export to Argentina.