High profile transgender personality Caitlyn Jenner has stated that girls sport must be protected. A candidate for California governor, Jenner was approached by a reporter during a coffee run on Saturday.

“This is a question of fairness,” said Jenner, who in 1976 won gold at the Olympics. “That’s why I oppose biological boys who are trans competing in girls’ sports in school. It just isn’t fair. And we have to protect girls’ sports in our schools.”

“I didn’t expect to get asked this on my Saturday morning coffee run, but I’m clear about where I stand,” Jenner later said in a tweet, sharing the TMZ interview. “It’s an issue of fairness and we need to protect girls’ sports in our schools.”

Trans activists are furious at the celebrity’s position but only have an emotion fuelled narrative to support their view. Jenner has science onside.

Kirralie Smith, spokeswoman for Binary, said the debate must be settled by biological reality.

“The full range of advantages possessed by biological males is undisputed. Testosterone, muscle mass, blood volume, lung capacity, bone structure and more provide all the evidence we need to legitimise separate sporting categories according to biology. Feelings and offence are not legitimate reasons to disadvantage females or to put them at risk on a sporting field. Common sense and evidence-based science must prevail to ensure a level and safe playing field for girls and women in sport.”