MADRID—Spain’s Pau Gasol says he will consider freezing a sperm sample because of concerns over Zika if he decides to play in the Rio de Janeiro Olympics.

Gasol says “freezing sperm is one of the measures I have to consider.”

The 35-year-old Chicago Bulls centre has yet to commit to playing for Spain. Gasol has led Spain to two consecutive silver medals after losing to the United States in the 2008 and 2012 finals.

In most known cases, Zika causes flu-like symptoms for a few days. But it has been blamed for a huge rise in Brazil of microcephaly, or babies born with abnormally small heads, and some cases of Guillain-Barre syndrome, which can cause paralysis, usually temporarily.

Last week, the partner of Olympic long jump champion Greg Rutherford said he would freeze a sample of his sperm because of fears of Zika.

John Speraw, 44, the coach of the U.S. men’s indoor volleyball team, said he is also preserving sperm to use for a planned future pregnancy in case he is infected with the mosquito-borne virus.

“My wife and I would like to have another kid,” he said recently at USA Volleyball’s training facility. “And I’m no spring chicken. I don’t want to get Zika and have to wait an additional year, or whatever it may be, for us to have kids. I’m paying attention to Zika and I’m concerned about it. It’s not going to stop me from going down there, but I’m taking measures right now.”

The virus is transmitted primarily by the Aedes aegypti mosquitoes, but there have been cases of Zika being transmitted sexually, too. The World Health Organization said this week that athletes and spectators, except for pregnant women, should feel comfortable attending the Olympics. Rio organizers will distribute 450,000 condoms to athletes, three times as many as were handed out at the London Games in 2012, largely in response to Zika.

Speraw’s wife, Michelle, and their 7-month-old daughter, Brooklyn, will not go to Rio because of concerns over Zika, he said. And an original travel-party list of about 10 family members and friends has been whittled to just his parents.

Speraw said the idea of freezing sperm has bounced around with other U.S. coaches and officials, and even some of his players, many of them married.

“I’m doing it because I’m 44,” he said. “I don’t want to wait and try to have a baby when I’m 46, you know? If we want to try next February, which was our original plan, then at least we can still do that.”