Sarah, 33, and husband Stephen welcomed son Stanley Roy into the world on Sunday and shared photos of the new arrival on Facebook.
The double world champion and Olympic bronze medallist already has a daughter, Elsie Diana, who was born in April last year.
Writing on Facebook, Sarah, who now goes under her married name Jennings, wrote: "After another traumatic entry to world by emergency section..here is our final member of Team Jennings - Stanley Roy Jennings, born 6/11/16 at 17.27 weighing 8lb. He is perfect and we are so in love again."
The tot's second name is a tribute to Sarah’s dad Roy who lost a battle with cancer in 2011.
The Bentley-born sports ace married her husband Stephen, current coach of the Great Britain national squad, six years ago and the couple now live in Liverpool.
She won GB’s first ever Olympic medal in taekwondo, a bronze, at the 2008 Games in Beijing, her third Olympic competition for her country.
Controversially eliminated before the medal rounds, she was reinstated following appeal and went on to win the bronze medal final.
She again became world champion in 2011, despite the loss of both her parents, to cancer in the proceeding year.
Sarah was selected for her home games in London in 2012, where she took the Olympic oath at the opening ceremony on behalf of all the athletes but missed out on a medal due to being hampered by injury in the build up to the competition.
In 2013, she announced her retirement from competition, and her intention to take up a coaching role in the Great Britain team, but she has since stepped down on the role to concentrate on being a mum.
She was made an MBE in the 2012 New Year Honours for services to martial arts and in January 2014 was made a freeman of Doncaster.