43-year-old Laurel Hubbard of New Zealand will make history when (s)he competes in the 2020 Summer Olympics, set to be held July 23 through August 8 of this year in Tokyo. Confused yet? We are, too. Here’s a quick breakdown of the conflicting yet true facts in that sentence:

• Laurel Hubbard was born a male named Gavin Hubbard and transitioned to living a female life in 2013 at age 35
• The Tokyo Summer Olympics are keeping the year they were originally scheduled to be held in their official name, because apparently they are the only organization in the world who wants to cling to the train wreck that was last year

Is it fair that a person who was born a male can compete against athletes who were born female on the world’s greatest stage? That issue has been hotly debated over the summer. The big question is ‘Will Hubbard enjoy an unfair advantage over cis women (those who were born female)?’

“There’s absolutely no question in my mind that trans women will maintain strength advantages over cis women, even after hormone therapy. That’s based on my clinical experience, rather than published data, but I would say there’s zero doubt in my mind,” sports physicist Joanna Harper told WebMD/Medscape.

She is a PhD student and trans woman who competed in races and published data comparing race times before and after transition. Harper included herself in that data, so she knows this subject well both as an athlete and a researcher.

Puberty brings hormonal changes that are unique to a person’s sex at birth, so men who transition to women after going through male puberty retain the physical benefits of added testosterone and overall height. Added height is an advantage for sports like basketball or volleyball. Harper suggests the rulemaking process should assess each event individually, rather than use a one-size-fits-all approach.

But for the 2020 Olympics, the International Olympics Committee (IOC) is operating under a rule reform from 2015 which states that transgender athletes are eligible to compete in the women’s division if their testosterone levels are below 10 nanomoles per liter of blood for at least 12 months prior to competition. Harper said cis women usually have level of less than 2 nanomoles per liter, and most trans women are under 2 as well. So, trans women like Hubbard will likely easily qualify under this rule, but retain the benefits of having lived the bulk of her life as a man, with natural levels of testosterone. Hubbard also competed in men’s weight lifting competitions until her transition, and the muscles built over all those years don’t disappear overnight.

Belgian weightlifter Anna Vanbellinghen will be competing against Hubbard and has been vocal about her opposition to Hubbard’s inclusion in the Games. She said it was unfair to women and “like a bad joke.” Vanbellinghen further said that “Life-changing opportunities are missed for some athletes – medals and Olympic qualifications – and we are powerless.”

Inclusion for all seems more like exclusion for some. Women’s sports have traditionally lagged behind men’s in all areas, from being included in competition rosters to funding and more. It seems that by allowing more diverse athletes to compete as women, the whole premise of women’s sports – that of women enjoying fair competition against evenly matched competitors – is being eroded.