Son-in-Law (22 April 1911 – 15 May 1941) was a British Thoroughbred racehorse and an influential sire, especially for sport horses.
The National Horseracing Museum says Son-in-Law is "probably the best and most distinguished stayer this country has ever known." [1]
Described as "one of the principal influences for stamina in the modern thoroughbred" in Ulbrich's Peerage of Racehorses, Son-in-Law is seen in the pedigree of many of the top 100 show jumpers, particularly those of Holstein heritage.
In 1924 and 1930, Son-in-Law was the leading sire in Great Britain and Ireland. His progeny include:
Foxlaw (1922-1935) - won 1927 Ascot Gold Cup
Straitlace (f. 1921) - won 1924 Epsom Oaks, Coronation Stakes
Rustom Pasha - extremely important sire in Argentina
Suzerain (f. 1933) - third in 1937 Jockey Club Cup, Doncaster Cup
Trimdon (f. 1926) - won 1931-32 Ascot Gold Cup