I think in the sense of "global elite athletics", no it by definition isn't fair. At all levels of sports funding is a significant entry barrier to elite competition. Biological advantages are everywhere too, irrespective of gender. Height, leg height, wing span, lung capacity, heart size, spinal curvature, basically every kind of biological parameter can create an advantage over someone else.

Thats an advantage those athletes havent earned. You don't earn a biological advantage, you just have it. You don't earn being born to a wealthy family who can finance your strict comprehensive training regimen, you just are born to one. If sports is about fairness, that is to say like, a level playing field anyone can come along and work really hard and compete, then no sports is not fair. Some people will be better than others no matter how hard they work.

Fairness in the sense of this discussion, is competition within your gender. Critics of trans inclusion are not objecting on biological grounds, they are objecting to a trans woman competing with cisgender women because they do not agree that she is a woman. These arguments about fairness are almost never applied to cis women with height or wingspan advantages. Just to trans women of any kind for competing at any level of competition.

If fairness is the goal, then sports needs to be extensively categorized based on all the biological parameters that give you an advantage. Or else some kind of combined leaderboard where everyones advantage or handicap is accounted for. Athletics competitions for people with disabilities already implement a combined leaderboard system in this way.

But no one is interested in actually being fair. They're interested in who does the absolute best. Who is the absolute best woman and who is the absolute best man. The disagreement is that trans women are women. There's nothing else they're concerned with precluding certain women from participating. They just disagree that trans women are women and therefore believe that in a "whos the absolute best woman at xyz" competition trans women should be excluded. To say that its a matter of fairness is demonstrably false.

Oh, and also your comment breaks one of the rules of this community. I'm leaving it up because I think it presents an opportunity to educate on exactly why this belief is wrong. But further comments to this effect will be removed. Please follow the rules of this community.