Serena and Venus Williams have been accused of a lot of things. But gender transformation wasn't among them. Until now.

The BBC is reporting that Russian Tennis Federation president Shamil Tarpischev has been fined $25,000 for referring to the Williams sisters as "the Williams brothers" on a television talk show.

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Tarpischev also has received a one-year ban from involvement in the Women's Tennis Association tour, according to the BBC.

The comments are "insulting, demeaning and have absolutely no place in our sport," WTA chief executive Stacy Allastar said.

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Tarpischev said he meant the comment strictly as a joke and meant no malicious intent, the report said further.

"I didn't want to offend any athlete with my words," Tarpischev said in a statement. "I regret that this joke has garnered so much attention. I don't think this incident deserves so much fuss."

The Russian tennis official went on to say that the Williams sisters "outstanding athletes" who "personify strength and perseverance."

Allastar said the WTA would not tolerate such flippant speech from one of its federation officials.

"Mr. Tarpischev's statements questioning their genders tarnish our great game and two of our champions," Allastar said. "His derogatory remarks deserve to be condemned and he will be sanctioned."

USTA president Dave Haggerty demanded that Tarpischev apologize for his thoughtless remarks.

"As the president of the Russian Tennis Federation and a member of the International Olympic Committee, Mr. Tarpischev is expected to conduct himself with the highest degree of integrity and sportsmanship," Haggerty said.

"Unfortunately, his comments do not embody either of these traits and in fact were reprehensible."

Serena is set to play in the WTA Finals in Singapore, the 2014 season-ending tournament beginning Monday. Williams is looking to finish another year as the No. 1 player.

Venus, who is battling Sjogren's syndrome that saps her energy (she was diagnosed in 2011), had a rebirth of her own, winning her first title in two years in February and improving her world ranking to No. 20. The former No. 1 player has seven Grand Slam titles.

Do you think the punishment for Russian Tennis Federation president Shamil Tarpischev's comments on the Williams sisters was appropriate? Comment below or tell us @SportsWN.