Parents of the University of Pennsylvania women’s swim team have written a letter urging the National Collegiate Athletic Association (NCAA) to change its rules on transgender athletes in response to Lia Thomas – a biological male – dominating the competition.

Obtained by the Daily Mail, the letter from the parents of 10 swimmers, sent on December 5, lamented that a new “precedent” has been set that could potentially destroy female sports.

“At stake here is the integrity of women’s sports,” the letter said. “The precedent being set – one in which women do not have a protected and equitable space to compete – is a direct threat to female athletes in every sport. What are the boundaries? How is this in line with the NCAA’s commitment to providing a fair environment for student-athletes?”