Caitlyn Jenner said transgender athletes born to male should not be allowed to compete in female sports teams.
Jenner recently announced she would run for governor of California as a Republican in an effort to overthrow Democrat Gavin Newsom.
The former Olympic decathlon medalist and reality TV star turned transgender in 2015.
During what appeared to be an impromptu interview while walking her dog, she told TMZ, “It’s all about fairness.
“This is why I oppose biological trans boys who participate in female sports at school.
“This is just not fair and we need to protect girls’ sport in our schools.”
When the reporter asked if such a ban “de-legitimizes” the identity of a trans person, Jenner did not answer the question, instead saying, “Have a nice day.”
She later shared the clip of the interview on Twitter, writing, “I didn’t expect to be asked this question on my Saturday morning coffee run, but I’m clear on my position.
“It’s a matter of fairness and we need to protect girls’ sport in our schools.”
The Florida legislature passed laws this week that would restrict entry to girls’ sports teams to those born female.
Similar laws have been passed in West Virginia, Alabama, Arkansas, Tennessee, and Mississippi.
The governor of South Dakota has issued an executive order, and dozens of other states are considering a legislature.
According to a study cited by TMZ, it hasn’t been conclusively proven that testosterone levels are a reason transgender women outperform their cisgender counterparts in certain sports.
Studies suggest that once trans girls start hormone therapy, their performance tends to stabilize, and many sports organizations require trans athletes to take hormone therapy.
Jenner has revealed only a vague glimpse of his political platform for the California race: cutting taxes, fixing the economy and ensuring balance in a state where politics is dominated by the Democratic Party.
She has a large social media following, with nearly 11 million Instagram followers and 3.5 million Twitter followers.