LONDON - Serena Williams says she thinks it isn't fair that she has been drug-tested more than other American tennis players this year.
Williams said at a pre-tournament news conference at Wimbledon: ''Just test everyone equally.''
She was asked about the issue on Sunday because of a recent Deadspin story that said Williams had been checked five times in 2018 by last month, more than other U.S. women and men in the sport.
Williams returned to competition this season after missing more than a year as a result of pregnancy. The 36-year-old American gave birth to a daughter last September.
Williams said she found it ''a little frustrating'' that she was deemed to have missed a test last month when a sample collector showed up at her house about 12 hours earlier than the time she had indicated she'd be available.
''I'm totally OK with testing and I encourage it,'' Williams said.
She added: ''It's just about being equal and not centering one person out.''