World number one Jason Day is the latest high-profile golfer to pull out of this summer's Rio Olympics because of concerns over the Zika virus.
The Australian, echoing four-time major winner Rory McIlroy who also withdrew last week, cited worries over health risks to his family for the decision.
"It is with deep regret I announce that I will not be competing in the 2016 Summer Olympic Games this coming August in Rio de Janeiro," Day said in a statement.
"The reason for my decision is my concerns about the possible transmission of the Zika virus and the potential risks that it may present to my wife's future pregnancies and to future members of our family."
Among the other golfers not going to Rio de Janiero in August because of Zika fears are Day's fellow Australian Marc Leishman, South African trio Branden Grace, Louis Oosthuizen and Charl Schwartzel, and Vijay Singh.
World number eight Adam Scott, and Northern Ireland's Graeme McDowell have declined to go for other reasons.
"I have always placed my family in front of everything else in my life," added Day.
"Medical experts have confirmed that while perhaps slight, a decision to compete in Rio absolutely comes with health risks to me and to my family.
"My wife Ellie and I have been blessed with two wonderful and healthy children and our plan is to have more.
"While it has always been a major goal to compete in the Olympics on behalf of my country, playing golf cannot take precedent over the safety of our family.
"I will not place them at risk. I hope all golf and Olympics fans respect and understand my position."