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|Birth date||2 1954|
Waterhouse was educated at the Kincoppal-Rose Bay School in Sydney, and completed a Bachelor of Arts at the University of New South Wales in 1975. The daughter of Randwick racehorse trainer TJ Smith, she made a name for herself as a model and actor, including in the Australian drama The Young Doctors before moving to England and appearing in the Doctor Who story The Invasion of Time. She then returned to Australia where she served an apprenticeship under her father for fifteen years before getting her own trainer's licence.
She was granted her Australian Jockey Club licence in January 1992, although this was made difficult as her husband, Robbie Waterhouse, was banned over his involvement in the Fine Cotton scandal. AJC rules at the time stipulated that the spouse of a banned person could not be licensed, although this was subsequently overturned. Her first winner was the horse Gifted Poet in March 1992, and her first Group One winner was Te Akau Nick in the Metropolitan Handicap in October that year. After TJ Smith became ill, he passed on the Tulloch Lodge stable to her in the 1994-95 season.
She was well-known to many Australians when Nothin' Leica Dane came into the Melbourne Cup in 1995 after winning the Victoria Derby three days earlier. The three year old colt ran second in the Melbourne Cup, a race which no three year old has won since Skipton in 1941.
In 1996-97 she had 10 Group One wins and won her first Sydney premiership. In 2001, Gai trifected the Golden Slipper and added the first of three successive Sydney training premierships, culminating with 156 wins in 2002/03, equalling her father's Sydney training record. In 2004/05 Gai had 11 Group One wins and added a fifth Sydney training premiership. As of the beginning of 2007 the Gai Waterhouse stable at Tulloch Lodge has won 75 Group One races.
Waterhouse's other successful horses include Golden Slipper winners Dance Hero, Ha Ha and the newly crowned 2008 Slipper winner Sebring, prolific Group One winners Grand Armee, Juggler, and All Our Mob as well as two time Epsom Handicap winner Desert War.
On 30 September 2000, she was awarded the Australian Sports Medal for "outstanding contribution to Thoroughbred Racing".
She is also an Australian Living Treasure nominated by the National Trust of Australia.
Gai was inducted into the Australian Racing's Hall of Fame in late November 2007. Her late father Tommy (T.J.) Smith is already an inductee.
- WATERHOUSE, (Gai) Gabriel Marie International Who's Who. accessed 3 September 2006.