The issue of transgender competition in women’s sports is coming to a head as sporting bodies start instituting new restrictions and as backlash mounts with more transgender female athletes winning elite women’s competitions.

A transgender female disc golfer, Natalie Ryan, was booted from a women’s tournament in California on Friday, after the Disc Golf Pro Tour won an appeal against a lower court ruling that had allowed Ms. Ryan to play. The appellate ruling meant that the tour could enforce the sport’s new, more restrictive policy with regard to transgender athletes. 

Ms. Ryan had already completed the first round of play in the OTB Open and was in fifth place when she was removed from the tournament, according to a disc golf news site, Ultiworld. Ms. Ryan is vowing to fight.

“My removal from OTB was targeted just as the new policy was,” Ms. Ryan said in a post to Instagram. “The DGPT is now enforcing rules that it has no place to. They have only done this to hurt me. I will continue to litigate until justice is achieved. I will use my pain to make sure nobody else has to experience it.”

A niche sport that has gained in popularity in the last few years, disc golf looks like a cross between golf and frisbee. There is a course like in golf, but players try to throw frisbee-looking discs into baskets, as opposed to using a club to get a ball in a hole. Top players earn money through sponsorship deals, and the average Professional Disc Golf Association tournament prize is more than $6,000.

Ms. Ryan, who won a major tournament in Michigan last year, filed a discrimination lawsuit against the disc golf league in February over its new transgender policy. The Professional Disc Golf Association’s new rule, instituted at the start of the year, states that transgender female players competing in the Pro Majors must maintain “a total testosterone level in serum below 2.0 nmol/L” for at least 24 months and have begun a “medical transition” prior to puberty. 

On Thursday, before the start of the weekend tournament, Ms. Ryan was granted a temporary restraining order in district court, allowing her to play. A Ninth Circuit Court of Appeals decision Friday reversed that.

“This order restores the DGPT’s ability to enforce its current policy on Gender Eligibility. The DGPT will follow the court’s ruling and enforce its Gender Eligibility Policy which will disallow Ms. Ryan from continuing competition in the OTB Open,” Disc Golf Pro Tour said in a statement.

Disc golf’s transgender policy, particularly regarding the age at which a person transitions, is one of the most restrictive in the sporting world. It comes as an about-face for a sport with a liberal reputation and a young following, and that just last June celebrated a transgender female player, Chloe Alice, for Pride Month.

“Disc golf is good for everyone — straight, gay, weird, normal, transgender, cisgender. It’s awesome, and it should be accessible for everyone,” Ms. Alice is quoted as saying on UDisc Disc Golf App’s Twitter page.

The Professional Disc Golf Association’s decision to institute rules around transgender competition came at the end of last year after the organization surveyed more than 33,000 players and found that 80 percent of women disagreed with the statement “transgender women should be allowed to compete with other women in disc golf and in other sports.” The league’s medical subcommittee also issued a report, saying, “In terms of fairness, no transgender person should ever be excluded. Also, with respect to fairness, the science is clear; males have a natural advantage over women.”

Other sports are following a similar path to disc golf. The international governing body for track and field, World Athletics, announced in March that only transgender women who have not gone through male puberty may compete in women’s international races. “It is precisely because there is insufficient evidence that the male advantage of male-to-female transgender athletes can be removed that World Athletics has made this decision,” a World Athletics representative told Science Insider.

The International Swimming Federation, also known as FINA, issued new guidance last June, barring transgender women who have gone through male puberty from competing at the highest levels of the sport. The change came after public outcry when a University of Pennsylvania transgender swimmer, Lia Thomas, won the NCAA championships and broke women’s records. Ms. Thomas had previously competed as a man for the first three years of her college career with only middling success.

USA Wrestling has also barred transgender women who have gone through male puberty from competing in women’s events. The International Rugby League has entirely barred transgender athletes from competing as women. Other sports have instituted regulations based on testosterone levels.

Speaking up about transgender participation in women’s sports is risky. After a transgender female cyclist, Austin Killips, won the Tour of the Gila race earlier this month, a three-time Olympic cyclist, Inga Thompson, went on Fox News to call on cycling’s international body to change its rules. “Start taking a knee at the starting lines. Team members need to speak up and protect their riders,” Ms. Thompson said, advocating a Black Lives Matter-style protest for women’s sports.

Ms. Thompson was promptly fired from her position on the board of an American pro-cycling team, Cynisca Cycling, for her comments.

Tennis legend Martina Navratilova is one of the most outspoken professional female athletes to come out against transgender participation in women’s sports. A former NCAA champion swimmer, Riley Gaines, has also become a face on this issue, working with the conservative Independent Women’s Forum to push legislation on transgender participation in sports.

Ms. Gaines started a Twitter campaign last week to call on other female athletes to make their stances known on these issues. She called on Venus and Serena Williams in particular. So far, though, no big names have taken the bait.