Rory McIlroy feels playing in this summer's Olympics is not worth the risk after announcing his withdrawal due to concerns over the Zika virus.
The Northern Irish world number four, who was due to represent Ireland in Rio in August, has become the latest high-profile golfer to say he will not travel to Brazil.
He follows Charl Schwartzel, Marc Leishman and Vijay Singh in pulling out over the Zika issue, which has cast a shadow over the build-up to the Games.
Four-time major winner McIlroy, 27, said in a statement: "After much thought and deliberation, I have decided to withdraw my name from consideration for this summer's Olympic Games in Rio de Janeiro.
"After speaking with those closest to me, I've come to realise that my health and my family's health comes before anything else.
"Even though the risk of infection from the Zika virus is considered low, it is a risk nonetheless and a risk I am unwilling to take. I trust the Irish people will understand my decision. The unwavering support I receive every time I compete in a golf tournament at home or abroad means the world to me.
"I will continue to endeavour to make my fans and fans of golf proud with my play on the course and my actions off it."
Zika is carried by mosquitoes and has been linked to defects in babies. The World Health Organisation declared the Zika epidemic to be a global emergency in February but its latest advice is that the risk of international spread as a result of the Olympics is "very low".
The International Olympic Committee, acting on WHO advice and with Brazilian authorities, is confident the situation is safe. The Games also take place during the South American winter, when there should be fewer mosquitoes.
Despite that, pregnant women have been advised not to travel to Brazil.
Britain's 2012 long jump gold medallist Greg Rutherford has had sperm frozen over Zika fears and American cyclist Tejay van Garderen, whose wife is pregnant, has also pulled out.
A statement from the International Golf Federation, the sport's Olympic governing body, read: "The IGF is disappointed with Rory's decision but recognises that some players will have to weigh personally a unique set of circumstances as they contemplate their participation in golf's historic return to the Olympic Games in Rio de Janeiro, with the Zika virus foremost among them.
"It is unfortunate that the Zika virus has led to Rory's decision to withdraw from the Olympic Games, knowing how much he was looking forward to taking part.
"As we have stated before, the Olympics is the world's greatest celebration of sport and we remain excited about golf's return after a 112-year absence."