Personal Ensign is possibly the greatest mare ever when taking into account the race record and her progeny. In addition to her 13-for-13 career record, her offspring include Grade 1 winner Miner's Mark, stakes winners Our Emblem (sire of '02 Derby winner War Emblem) and Traditionally.
Her best foal was the filly My Flag, who won the 1995 Juvenile Fillies and was 3rd in the 1996 Belmont. Six year's later, My Flag's daughter Storm Flag Flying took to the track for the Juvenile Fillies as the heavy favorite to make it 3 generations with Breeders Cup wins.
To show you how fickle breeding is, this was My Flag's best foal by a mile--she hasn't produced another stakes winner since. And Storm Flag Flying's first foal has been nothing special. In breeding, you just never know.