There’s no feeling of triumph in International Association of Athletics Federations (IAAF) circles in the wake of yesterday’s landmark ruling by the Court of Arbitration for Sport supporting their "eligibility regulations for the female classification for athletes with differences of sex development".

In its press release, the IAAF said it was “pleased the regulations were found to be a necessary, reasonable and proportionate means of achieving the IAAF's legitimate aim of preserving the integrity of female athletics in the restricted events".

At best, perhaps, there is a sense of sombre relief that the profound puzzle of how to manage the conflicting interests of different groups of athletes within the sport – as the CAS ruling put it, a complex of conundrums – has been put into some kind of definitive shape. Even if there are pieces that still lie awkwardly on the periphery.

Were he minded to do so, the IAAF President Sebastian Coe could move into Churchillian mode and muse upon the fact that it is not the end, nor the beginning of the end, but perhaps the end of the beginning.

But then this not a battle – at least as far as the IAAF sees it. Those supporting the appeal against their eligibility regulations of Caster Semenya, the South African runner who, entirely naturally, has dominated women’s middle-distance running over the past four years, may feel differently. Legal options may still be open to them.

The panel pointed to three peripheral pieces in particular. The first related to the difficulty some athletes may have in regulating, monitoring and managing their testosterone levels to the required degree. This is going to be an area requiring particular sensitivity and, as far as possible, flexibility, with the ruling principle of “strict liability” – that an athlete is responsible for whatever is in their body – perhaps needing to take on a new shape.

Questions were raised from a scientific point of view about a particular difficulty identifying evidence of significant athletic advantage by a sufficient number of 46 XY DSD athletes in the 1,500m and the mile events.

The CAS panel suggested the IAAF consider deferring the application of the DSD regulations to these events until more evidence is available.

But the IAAF has retained these distances in its regulations – and maintains its rights to reduce, or increase, that list in future.

CAS also claimed the side effects of hormonal treatment experienced by individual athletes could, with further evidence, demonstrate the practical impossibility of compliance, which could, in turn, lead to a different conclusion as to the proportionality of the DSD regulations.

In its response to the ruling, the IAAF confirmed that the regulations would come into effect from May 8, adding that “relevant athletes” already due to compete at the opening IAAF Diamond League meeting of the season in Doha tomorrow “are eligible to compete at that competition (including in restricted events) without decreasing their testosterone level below 5 nmol/L.”

Both Semenya, and Burundi’s Rio 2016 silver medallist Francine Niyonsabo, who confirmed last month that she was also an athlete coming into the DSD category, are provisional starters in the 800m.

The IAAF reiterated that the eligibility conditions “require a relevant athlete to reduce her testosterone levels to below 5 nmol/L for a continuous period of at least six months prior to competition in the female classification in a restricted event at an international competition.”

The IAAF response adds: “As a special transitional provision to ensure the delay caused by the legal challenge to the regulations does not prejudice relevant athletes, the IAAF will accept that relevant athletes who comply with the 5 nmol/L limit starting on or before May 8, 2019 will be eligible for the IAAF World Championships Doha 2019, assuming they meet the other required eligibility conditions.”

But if any athletes have proceeded on the assumption, or hope, that the IAAF ruling would not be upheld by CAS, they are now looking at a blank season from May 8 onwards.

In its executive summary, published soon after the initial decision yesterday, CAS characterises the case thus: “By a majority, the CAS panel dismissed the requests for arbitration considering that the claimants could not establish that the DSD regulations were ‘invalid’.

“The panel found that the DSD regulations are discriminatory but that, on the basis of the evidence submitted by the parties, such discrimination is a necessary, reasonable and proportionate means of achieving the legitimate objective of ensuring fair competition in female athletics in certain events and protecting the ‘protected class’ of female athletes in those events.”

The crucial part of this summary is section 21. Before the ruling was announced, there were reports, which emanated from those supporting Semenya’s cause, that the IAAF still had not got the science nailed down on this question – which would have left them without any leverage.

There were also suggestions that athletic performance by female athletes was not directly proportionate to the levels of testosterone in their body.

In a long and thoughtful piece written by Andy Brown for, the central issue is well expressed: "The IAAF’s eligibility regulations for the female classification (athletes with differences of sex development), to give the regulations their full snappy name, are designed to regulate athletes with one of seven listed DSDs competing in international events run between 400m and one mile in the IAAF female category, if their testosterone levels are above 5nmol/L and have an ‘androgenising effect’ (i.e. if that testosterone is taken up by their androgen receptors and boosts their physiology).”

Section 21 of the CAS Executive Summary says this: “It was common ground between the parties that there is a substantial difference in elite sports performance between males and females. It was also common ground that (a) the normal female range of serum testosterone, produced mainly in the ovaries and adrenal glands, is 0.06 to 1.68 nmol/L; and (b) the normal male range of serum testosterone concentration, produced mainly in the testes, is 7.7 to 29.4 nmol/L.

“On the basis of the scientific evidence presented by the parties, the panel unanimously finds that endogenous testosterone is the primary driver of the sex difference in sports performance between males and females.”

Sections 22-24 are also highly pertinent: “The IAAF submitted that all but one of the many different factors that contribute to sport performance – including training, coaching, nutrition and medical support, as well as many genetic variations – are equally available to men and women. The only factor that is available only to men is exposure to adult male testosterone levels.

“The IAAF submitted that if the purpose of the female category is to prevent athletes who lack that testosterone-derived advantage from having to compete against athletes who possess that testosterone-derived advantage, then it is necessarily ‘category defeating’ to permit any individuals who possess that testosterone-derived advantage to compete in that category. The majority of the panel accepts the logic of the IAAF’s submission.

“23. Having carefully considered the expert evidence, the majority of the panel concludes that androgen sensitive female athletes with 46 XY DSD enjoy a significant performance advantage over other female athletes without such DSD, and that this advantage is attributable to their exposure to levels of circulating testosterone in the normal adult male range, rather than the normal adult female range…

“24. On this basis, the majority of the panel accepts that the IAAF has discharged its burden of establishing that regulations governing the ability of female athletes with 46XY DSD to participate in certain events are necessary to maintain fair competition in female athletics by ensuring that female athletes who do not enjoy the significant performance advantage caused by exposure to levels of circulating testosterone in the adult male range do not have to compete against female athletes who do enjoy that performance advantage.”

In section 12 of the Executive Summary, CAS notes: “This case involves a complex collision of scientific, ethical and legal conundrums. It also involves incompatible, competing rights. It is not possible to give effect to one set of rights without restricting the other set of rights.”

In confirming that she had the same kind of hyperandrogenism as Semenya, Niyonsaba said: "For me, it's about discrimination. It doesn't make sense. I didn't choose to be born like this. What am I? I'm created by God."

I’m thinking back now to the press event ahead of last year’s first IAAF Diamond League final, held in Zurich’s Letzigrund Stadium. With other athletes either side of her, Semenya was ruefully acknowledging that she was coming towards the end of a long, fruitful season – “I broke a record. If you want to ask about records now, I’m exhausted! My main focus is to run a smart race. If I move I move, but the main focus is to win a Diamond Trophy.”

She was relaxed. She was funny. She was thoughtful.

“I think running is never difficult, if I may say. You stick to your plans – it’s about you mentally, how well prepared you are. With the training we do we never want that to change. We want to make it easy to run. With the team I have around me, we do crazy things on the track so it becomes easy for me to run.

“I respect my opponents and I expect the same thing. It’s not about what happened in Lausanne or Monaco. It’s all about what is going to go down tomorrow. A different field. A new day – try to improve times.

“The ultimate goal is to entertain people and to make meet organisers and sponsors happy, I enjoy every day when I run. I feel increased. “

Tragedy is a term overused. Tragedy is not an accident. It is something that circumstances, multiple circumstances, make awful and inevitable. In those terms, what has happened to Semenya and others who were born with her physiological make-up is - solely in sporting terms - tragic.