You achieve the burden of proof the wrong way around. We know that male developement is advantageous. That’s why we have the categories in the first place. The burden now is on the claim that lowering T negates the benefits of androgenised male development. the evidence does not currently support this.Goes without saying that there's a margin of error in the calculation because it treats age 30 as a binary divide, the point is that the percentage of transgender people aged 29 or below is too high to treat there being 0 transgender athletes in the top-150 of women's cycling as an indicator of a level playing field.
The number would be a problem in terms of fairness if the percentage of top-level transgender athletes outpaces the percentage of transgender women overall in a statistically significant way. So the percentage of transgender women in cycling should increase as younger generations whose ability to identify as the people they are is less impeded by transphobia (and other forms of bigotry) become the generations who make up the peloton. In other words, a rising number of transgender women's cyclists will not necessarily indicate a problem.
In fact, if in a couple of decades we live in a world where 5% of younger adults identifies as trans and there is still zero trans representation higher up in the women's rankings, we're likely also looking at a statistically significant difference. That would also be a problem in terms of fairness, either due to institutional transphobia in cycling or due to the relative strictness of the rules under which transgender athletes are allowed in this sport giving them an inherent disadvantage compared to cisgender athletes.
We'll cross either of those bridges if we get there, but right now there is a lack of proof to conclude that transgender women have an unfair (dis)advantage. That includes not only the presence of transgender women at the highest level of sport, but also the body of peer-reviewed scientific work in this field, which has produced mixed evidence in spite of what some people will claim.
The only two papers that purport to show data to support the negation of advanatge are Chicarelli and Roberts. Both used USAF fitness test data. Thats’s not a valid data set to use As its a test to see if a target can be hit not what the participants maximal performances is. As Chicarelli puts it “This is a fundamentally different question as military fitness testing aims to set a standard above which individuals demonstrate basic physical performance capabilities and maximize medical readiness, rather than quantifying the ceiling of human performance in a cohort.”
It is further invalid because as soon as trans women a start to fail to meet the male target they are moved to only having to hit the female target. It is therefor no surprise that once their target is lowered theit performance drops to me that new lowered standard.
No other studies claim to have data showing the negation of benefit. Gooren showed that hgb is equalised but that same study showed that cross sectional muscle mass remains above female levels.