"With the Grand Slams there are so many opportunities to win," said Venus Williams after taking the singles and doubles titles at the Sydney Olympics.
"A gold medal, it's just once every four years and who knows what might happen between now and 2004."
JENNIFER REN FACTS
Born: January 21 1993
Honours: 2006 U14 doubles title British Nationals, third in 2005 Orange Bowl, 2005 U12 British Nationals
Favourite player: Kim Clijsters
Venus and Serena may have been the first sisters to dominate at an Olympics, but Britain has some tennis siblings who are eyeing up the chance of glory in 2012.
In a quiet corner of Sheffield, two sisters are pounding the courts six days a week as they build the foundations for what they hope will be top-level careers.
Jennifer Ren, aged 13, and sister Jessica, 12, are rated in the world's "top ten in their age groups" by their coach, former Davis Cup player John Clifton who has mentored the pair since they were eight.
Clifton says: "If they do manage to keep moving forwards then they would be the right age (to compete at the Olympics).
"But the cards are re-dealt every year. You just never know whether they are going to develop physically, mentally and whether they keep on working.
"They've put in a lot of work so far I just hope that it continues. They are the hardest working juniors that I've coached."
Unlike Venus and Serena, the Ren sisters do not have the shadow of an influential father hanging over them.
In fact their parents claim to have little sporting prowess. Both academics, they arrived from China 16 years ago and settled in Sheffield to study architecture.
The girls' father, Alan, introduced the girls to tennis and now escorts them as they play in some of the world's biggest junior competitions.
"They don't really get their competitiveness from their parents," he laughs.
"We try to emphasise a good education although it's getting difficult with all the travelling and tournaments they play in."
When we're playing against each other our relationship isn't that good...we just wind each other up
Keeping the girls grounded has been a success so far. If Jennifer didn't make it as a tennis player, she says she would like to attend a good university.
"It's not the stardom they're after," Alan says, "but that comes with the success.
"They are normal kids, they go through all the emotions, and they like to do everything well; their school work and their tennis."
That kind of dedication has already paid dividends and has helped what appears to be a healthy sibling rivalry.
Jennifer says: "When we're playing against each other our relationship isn't that good because we argue quite a lot, we just wind each other up.
"Off the court we're okay, but there's still a bit of rivalry."
Jessica adds: "I've only won twice in tournaments (against Jennifer). Every other time she's beaten me.
"We shout when we lose a point, we make comments we shouldn't say and then in practice matches, we argue about the score, the line calls and everything.
"Sometimes we don't get much tennis done," she adds, laughing. "Our parents have walked off and left us to it at times."
Whatever their relationship on and off the court, others have been impressed by their work ethic.
In 2005 they went to the renowned Nick Bollettieri Tennis Academy, where the legendary coach called them "darn good", and they are due back there this autumn.
JESSICA REN FACTS
Born: 23 August 1994, Sheffield
Honours: 2006 U14 doubles title British Nationals
Favourite players: Roger Federer, Rafael Nadal, Kim Clijsters
The pair will also compete in the Orange Bowl, regarded as the world's unofficial junior championships, with Jennifer looking to improve on her third place last year.
But it's not all jet-setting and meeting world-famous coaches. The constant slog means the girls have to make sacrifices.
"I miss going out with my friends a bit," admits Jennifer. "I just do the core subjects at school and my friends are a bit jealous when I shoot off.
"It's hard to keep the focus sometimes but I suppose if you want to be good you need to have focus.
"I've made my mind up already, I want to be a tennis player."
Jessica adds: "I'm competitive. I don't like to lose, I don't give up usually. I don't have many days when I'm playing very badly.
"I'd like to do well at Wimbledon and be in the world's top ten. That's our goal really, to do what Andy Murray and Tim Henman did for women's tennis."
With the pair admitting to being excited by the Olympics, what price a Ren sisters gold in London in 2012?