Olympic men's doubles champions Bob and Mike Bryan have pulled out of Rio 2016 to protect their "family's health".
The American duo's announcement comes after fellow tennis stars Milos Raonic, Simona Halep and Tomas Berdych withdrew from the Games over the Zika virus.
In a statement, Bob Bryan said he and his brother made the decision after "countless hours of deliberation".
"Though we'd love to compete again, as husbands and fathers our family's health is now our top priority."
Women's world number five Halep and men's world number seven Raonic were the first tennis players to make themselves unavailable because of Zika, which is linked to brain deformities in newborn babies.