Former Olympian Rebecca Dussault says 'it's a sad day for sport' when transgender athletes are allowed to compete in women's events.

The American cross-country skier, who took part in the 2006 Winter Olympics in Italy, is not the only sportswoman to have spoken up about the issue, with Martina Navratilova and Mary Peters also voicing their concerns.

And Dussault is worried about the records that will tumble in women's sport if transgender athletes are allowed to compete.

She said: “We invest so much money into keeping sports fair and this blows the cap off of it. Every woman’s record in sports will fall.

“I can tell you beyond a shadow of a doubt there are 1,500 men who on their bad day can beat Serena Williams in tennis.

“There are 2,000 men who could outrun the fastest female sprinters of all time. So if one of them deciders to compete as a trans woman, there you go.”

Athletes were allowed to 'self-identify' as their preferred gender in the Canada Winter Games earlier this year irrespective of biological differences.

And the 38-year-old believes a third category for transitioning athletes could be the answer, however maintaining the competitiveness of women's sport must not be compromised.

She said: “We cannot take the time to hyper-categorize people, it absolutely wouldn’t work to get into the nitty gritty of categorizing people based on lung capacity or arm length or anything other than XX or XY [chromosomes], and maybe there can be a third category but it cannot encroach upon the dignified competition of woman vs. woman."

Dussault questions both women and men as to why more are not speaking out against the movement towards transgender athletes being able to reassign their sporting classification.

“It’s a sad day for sport if we’re going to just put up with this,” she told the Daily Caller News Foundation.

“Where are the women who will stand up for women? There are so many women who will stand up for women’s rights in every other possible thing, but when it comes to sports, we’re just going to be spineless? Where are these great champions who aren’t speaking out on this?

“Where are the men standing up for this? Where are the men defending women’s sports?

“I’m sorry, but the men are fine and safe, they’re on high ground, but we’re about to go in on the undertow, as women in sport. And so, I call out the male champions there too: where is your voice? Where is your spine?”