Martina Navratilova was involved in a heated row about transgender athletes in women's sport.

Tennis great Martina Navratilova has sparked outrage among the transgender community after saying that people who were born male shouldn't be allowed to compete in women's sport.

The 17-time Grand Slam champion from the Czech Republic was commenting on Twitter about transgender women in sport and she was accused of being "transphobic".

Navratilova, who was responding to a question from one of her followers, said: "Clearly that can't be right. You can't just proclaim yourself a female and be able to compete against women. There must be some standards, and having a penis and competing as a woman would not fit that standard."

GETTY IMAGES Navratilova is widely considered the greatest women's tennis player of all time.

She added: "For me it's all about fairness. Which means taking every case individually… there is no cookie cutter way of doing things."

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Kiwi transgender weightlifter Laurel Hubbard, who previously competed as a man, was a divisive figure in the women's event at the 2018 Gold Coast Commonwealth Games after making the transition to become female.

AP Kiwi transgender athlete Laurel Hubbard failing to make a lift in the snatch of the women's +90kg weightlifting final at the 2018 Commonwealth Games.

​Navratilova's comments prompted angry responses from Dr Rachel McKinnon, who controversially won a women's event at the UCI Masters track world championships.

McKinnon, a Canadian cyclist and transgender activist, was born a male before becoming a female in her 20s and her victory at the Los Angeles event in October sparked controversy as she towered above her rivals on the podium.

Responding to Navratilova, McKinnon demanded the 62-year-old apologise among several critical tweets.

RACHEL MCKINNON/TWITTER Transgender woman Rachel McKinnon, centre, celebrates her first-place finish at UCI Masters track cycling world championships in Los Angeles in October.

"Genitals do not play sports. What part of a penis is related to tennis? How does that 'level' any playing field?"

McKinnon, 36, added: "You realise I'm a world champion trans woman athlete?"

Navratilova apologised after deleting her original tweet but she hit back after McKinnon's scathing comments continued, saying: "Rachel, you might be an expert on all things trans but you are one nasty human being."

You got that right. To all the people on this thread- I am totally and completely pro- trans people or any part of the spectrum. I do not wish to define anyone. All I want is fairness on the playing field. That is it. How we get to that is a discussion for the ages… — Martina Navratilova (@Martina) December 20, 2018

No, you are not "pro- trans people" if you say that trans women with a penis must not compete in women's sport. That's transphobic.



Genitals do not play sports. What part of a penis is related to tennis? How does that 'level' any playing field? https://t.co/h7ZLsCVOQy — Dr. Rachel McKinnon (@rachelvmckinnon) December 20, 2018

McKinnon regularly tweets about transgender topics.

Earlier, Navratilova said: "I am sorry if I said anything anywhere near transphobic – certainly I meant no harm. I will educate myself better on this issue but meantime I will be quiet about it."

Navratilova added that she did not regret her original comment but McKinnon's criticism went on.

Happy thoughts going out to all my trans and queer siblings, especially if today is one of the hardest days of the year.



You are loved.



You are worth loving.



💜🌈🦄✊ — Dr. Rachel McKinnon (@rachelvmckinnon) December 25, 2018

She said: "It doesn't change the fact that you did something very wrong today. Past good deeds don't give someone a pass."

McKinnon this month told the BBC she received more than 100,000 hate messages on Twitter after her world championship success in October.

Jen Wagner-Assali, who finished third in the event, called McKinnon's victory unfair and wanted cycling's international governing body to change the rules.

Navratilova, who is widely considered the greatest women's tennis player of all time, came out as bisexual in 1981 and she is an activist for LGBT rights.