Golfer Rory McIlroy became one of the most high-profile sports stars to opt out of the Rio de Janeiro Olympics because of concerns about the Zika virus, saying Wednesday it is “a risk I am unwilling to take.”

“After speaking with those closest to me, I’ve come to realize that my health and my family’s health comes before anything else,” the four-time major winner said in a statement released by his management company.

The 27-year-old McIlroy said this month that he and his fiancee, Erica Stoll, may consider starting a family “in the next couple of years.” Zika is a mosquito-borne virus which has been linked to severe birth defects and possible neurological problems in adults.

“Even though the risk of infection from the Zika virus is considered low,” McIlroy said, “it is a risk nonetheless and a risk I am unwilling to take.”

The fourth-ranked McIlroy was scheduled to play for Ireland as golf makes its return to the Olympics for the first time since 1904.

The Olympic Council of Ireland (OCI) said it was “extremely disappointed” not to have McIlroy on its team.

“However, as we have always said, it is down to the individual and of course we respect his decision, which he has taken for personal reasons,” the OCI said in a statement.

Next in line for the Irish would be Graeme McDowell of Northern Ireland, whose wife is expecting their second child about two weeks after the Olympics. If he chooses not to play, the spot would fall to Padraig Harrington.

Marc Leishman of Australia and Charl Schwartzel of South Africa are golfers to have already pulled out of the Olympic tournament specifically because of Zika. Leishman cited concerns over the health of his family — his wife, Audrey, nearly died last year from toxic shock syndrome — while Schwartzel has said he and his wife intend to have more children and the risk of getting the virus is too great.

American cyclist Tejay van Garderen is another sportsman to cite Zika as the reason behind not going to Rio. Basketball star Stephen Curry has dropped out of the games, not specifically citing Zika but noting that “other factors” played a role in the decision.

Adam Scott, Louis Oosthuizen and Vijay Singh are other golfers to have also said they won’t compete at Rio, mostly due to scheduling commitments.

This might not be the last of golfers to pull out. Jason Day, the No. 1 player in the world, earlier this month began to raise doubts that he would go to Rio because of Zika. They have two children, and he said his wife wants more.

“I don’t think it’s an Olympic issue. I don’t think it’s a Rio issue,” Day said at the Memorial. “I just think it’s a medical issue attached to what happens if I go there, get it and bring it back. They don’t know. The recommendation from the CDC (Centers for Disease Control and Prevention) is ‘x.’ You don’t know how long it’s going to last in your body. So I’m a little wary about it.

“I’ve just got to make a smart, educated decision whether to go or not.”

Last month, 150 health experts issued an open letter to the U.N. health agency calling for the games to be delayed or relocated “in the name of public health.” The agency, the World Health Organization, responded that such steps would “not significantly alter the international spread of Zika virus.”

The OCI said it has been taking its lead on the Zika situation from the International Olympic Committee.

“They have provided us with every assurance and we have total confidence that the games will be safe for all athletes,” the Dublin-based organization said.

McIlroy had been eligible to compete for either Britain or Ireland at the Olympics. The four-time major champion eventually chose Ireland, which he had represented throughout his amateur career and twice in the World Cup.

“I trust the Irish people will understand my decision,” McIlroy said. “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 endeavor to make my fans and fans of golf proud with my play on the course and my actions off it.”

The International Golf Federation said it was “disappointed” with McIlroy’s decision but “recognizes 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 added that “the Olympics is the world’s greatest celebration of sport and we remain excited about golf’s return after a 112-year absence.”

The IGF, founded in 1958, is recognized by the IOC as the official world body for golf.