Tennis star Serena Williams on Tuesday suggested discrimination may be behind her frequent drug testing. “It’s that time of the day to get ‘randomly’ drug tested and only test Serena. Out of all the players it’s been proven I’m the one getting tested the most. Discrimination? I think so,” she wrote on Twitter. Williams, who made it to the Wimbledon final earlier this month just 10 months after giving birth, has reportedly already been tested at least five times this year—more than any other player, according to Deadspin. Despite questioning why she has been singled out with the latest drug testing on Tuesday night, Williams said she’s “ready to do whatever it takes to have a clean sport so bring it on.” “I’m excited,” she tweeted.