The Kissing Defence: Contrasting Outcomes in Thibus and Oliveira Cases

This article examines the so-called ‘Kissing Defence’: where an athlete facing doping allegations argues that the prohibited substance entered their system through contamination by intimate contact – usually kissing – rather than by deliberate doping. It compares two recent cases which reached contrasting outcomes on Kissing Defences: WADA v FIE & Ysaora Thibus (CAS 2024/A/10748) (Thibus)^[1], where the argument succeeded, and International Tennis Integrity Agency v Gonçalo Oliveira (SR/140/2025) (Oliveira) [2], where it failed.

This article is split into two parts with Part 2 available here. This Part 1 examines the above two decisions in Thibus and Oliveira and compares the reasons behind the differing conclusions reached by the respective panels.

Part 2 compares these two cases with previous awards and identifies the evidential, scientific and legal requirements that determine success or failure in establishing the Kissing Defence. It also examines how recently approved changes to the 2027 WADA Code may make such defences more common in the future.

Introduction

One of an athlete’s best routes to minimising sanctions after an anti-doping rule violation (ADRV) is to argue that the ADRV was not intentional and arose through no fault or negligence of their own. However, establishing such a defence is easier said than done.

Some athletes have successfully established that defence by identifying an alternative route by which the prohibited substance entered their system. While still relatively rare, in a growing number of cases athletes have relied on Kissing Defences, arguing that the prohibited substance entered their system by intimate contact.

For example, in Thibus the former world champion fencer Ysaora Thibus (YT) successfully relied on the Kissing Defence – and avoided any ban whatsoever – following the identification of ostarine in her sample. This stands in contrast to the decision in Oliveira, in which tennis player Gonçalo Oliveira (GO) unsuccessfully raised a Kissing Defence in respect of methamphetamine detected in his sample. Subject to any appeal to the Court of Arbitration for Sport (CAS), GO has been banned from competition for four years^[3].

Despite its somewhat unusual character, the Kissing Defence is becoming increasingly common. This may be unsurprising given research indicating that anabolic steroid use often occurs among nonathletes engaged in e.g. recreational bodybuilding^[4], increasing the risk of transfer to athlete partners. Indeed, a significant number of Kissing Defence cases over the past few years deal with alleged contamination by intimate contact with partners who had taken anabolic steroids or selective androgen receptor modulators (SARMs) for recreational purposes. For example, see: American softball player Madilyn Nickles (ligandrol) in 2020;^[5] Canadian world champion canoeist Laurence Vincent Lapointe (ligandrol) in 2020;^[6] Ukrainian tennis player Dayana Yastremska (mesterolone) in 2021;^[7] Canadian curler Briane Harris (ligandrol) in 2025;^[8] and Swiss triathlete Imogen Simmonds (ligandrol) in 2025^[9].

Article Outline

• Legal Framework for Doping Violations
  • Strict Liability
  • Sanction
  • No Fault or Negligence & No Significant Fault or Negligence
  • Standard of proof & intentionality
• Background of the Thibus case
  • Proceedings before the Doping Disciplinary Tribunal of the FIE
  • Appeal before CAS & Award
• Background of the Oliveira case
  • The use of the Kissing Defence
  • Decision of the Independent Panel
• Comparison
  • Proving Fact and Extent of Partner Use
  • Balance of Probabilities Threshold
  • Scientific Evidence