Martina Navratilova has criticised the "silence" of the International Tennis Federation after comments from one of its members about the Williams sisters.
Russian Tennis Federation president Shamil Tarpischev described world number one Serena Williams and older sister Venus as "brothers".
The Women's Tennis Association banned him for a year and fined him £15,500 but Navratilova wants ITF action.
"The silence from the ITF has been pretty deafening," Navratilova said.
"They are the ones who actually have the possibility of doing something as Tarpischev is head of the Russian Tennis Federation, which falls under the ITF and is also Fed Cup captain which falls under the ITF.