Related Rule
Germany
Practice Relating to Rule 92. Mutilation and Medical, Scientific or Biological Experiments
Germany’s Military Manual (1992) provides:
606. It is prohibited to subject wounded, sick and shipwrecked persons to any medical procedure which is not consistent with generally accepted standards. In particular, it is prohibited to carry out physical mutilation, medical or other scientific experiments or removal of tissue or organs for transplantation.
608. The wounded and sick have the right to refuse any surgical operation and similar manipulation, in which case medical personnel shall request a written statement to that effect, signed or acknowledged by the patient. Simple diagnostic measures, such as the taking of blood, shall be permitted, as shall measures necessary to prevent, combat and cure contagious diseases and epidemics. 
Germany, Humanitarian Law in Armed Conflicts – Manual, DSK VV207320067, edited by The Federal Ministry of Defence of the Federal Republic of Germany, VR II 3, August 1992, English translation of ZDv 15/2, Humanitäres Völkerrecht in bewaffneten KonfliktenHandbuch, August 1992, §§ 606 and 608.
The manual further states that conducting biological experiments is a grave breach of IHL. 
Germany, Humanitarian Law in Armed Conflicts – Manual, DSK VV207320067, edited by The Federal Ministry of Defence of the Federal Republic of Germany, VR II 3, August 1992, English translation of ZDv 15/2, Humanitäres Völkerrecht in bewaffneten KonfliktenHandbuch, August 1992, § 1209.
Germany’s Law Introducing the International Crimes Code (2002) provides for the punishment of anyone who, in connection with an international or non-international armed conflict, mutilates a person who is to be protected under international humanitarian law or who exposes a person who is to be protected under international humanitarian law to the risk of death or of serious injury to health
a) by carrying out experiments on such person and who has not consented in advance or whether the experiments concerned are neither medically necessary nor carried out in his or her interest,
b) by removing tissue or organs from such a person for transplantation purposes, save where blood or skin is taken for therapeutic purposes consistent with generally recognized medical principles and where the person has freely and expressly consented in advance, or
c) by using on such persons methods of treatment which are not medically recognized, without there being any medical necessity for doing so and without the person having freely and expressly consented in advance. 
Germany, Law Introducing the International Crimes Code, 2002, Article 1, § 8(1)(3) and (8).