Canadian Rachel McKinnon finished ahead of the field at the women’s sprint 35-39 age bracket at the world cycling championship on Sunday. Many have praised her achievement, but some say it was cheating, since she was born male.

McKinnon is the "first" transgender woman ever to win gold at the UCI Masters Track Cycling World Championships. The event was organized by USA Cycling and took place in Los Angeles under the auspices of the International Cycling Federation (ICF).

Before the final race, McKinnon set a world record in the quarterfinals – which only stood for 10 minutes.

I broke the 200m WORLD RECORD this morning. It was my first indoor 200m and I have to admit that my 11.92 was significantly slower than I was doing outdoors in the summer. I still need… https://t.co/B2AVmn6aDq — Dr. Rachel McKinnon (@rachelvmckinnon) October 12, 2018

She celebrated her victory by posting a photo of herself on the podium with the silver and bronze medalists.

The victory was praised by some, who congratulated her and called it an “incredible achievement.”

Others, however, claim the champ has an unfair advantage and should not be allowed to compete with women. Some commenters took aim at McKinnon’s size, pointing out the disparity between her and her competitors.

Unfair advantage and not to be celebrated. Look at the difference in size and muscle mass. Of course you were going to win. — Libs G (@libsg41) October 14, 2018

Those poor women who trained so hard only to have this done to them. — Shatner’s Bassoon (@stringfella_) October 14, 2018

Critics say the cyclists that competed against her were robbed of victory because she is biologically male.

Amazing! I was so enthused at reading this, I went out and challenged two 8 year olds to a 100m race. Guess what, I ONLY WENT AND FUCKING WON. First time running in a 8 year old’s race too! — James (@Hitkicker) October 13, 2018

McKinnon fired back, tweeting that she has to keep “an unhealthily low endogenous testosterone value” which is “virtually undetectable.”

Well, no, I'm still forced to have an unhealthily low endogenous testosterone value...it's virtually undetectable it's so low...way below the average for women. https://t.co/yoSsTF6BI5 — Dr. Rachel McKinnon (@rachelvmckinnon) October 14, 2018

She also claimed the cyclists who finished 2nd and 4th in the race were “strong supporters” of hers, and accused her critics of bigotry and transphobia.

2nd and 4th are friends and STRONG supporters of mine. ...hater https://t.co/CMOFjhlucA — Dr. Rachel McKinnon (@rachelvmckinnon) October 14, 2018

Apart from being a professional athlete, McKinnon is a PhD in philosophy and focuses on gender studies.

She argues that transgender women should be allowed to compete at the Olympics without being required to maintain their testosterone at a certain level.

“This is bigger than sports and it’s about human rights,” McKinnon told US Today in January, arguing that there is no way to measure the advantage testosterone gives transgender athletes. She went further, comparing discrimination against transgender athletes to racism in sports.