CRC/C/GC/10 page 12 the child, for example, is accused of committing a serious offence or where the child is considered mature enough to be held criminally responsible. The Committee strongly recommends that States parties set a MACR that does not allow, by way of exception, the use of a lower age. 35. If there is no proof of age and it cannot be established that the child is at or above the MACR, the child shall not be held criminally responsible (see also paragraph 39 below). The upper age-limit for juvenile justice 36. The Committee also wishes to draw the attention of States parties to the upper age-limit for the application of the rules of juvenile justice. These special rules - in terms both of special procedural rules and of rules for diversion and special measures - should apply, starting at the MACR set in the country, for all children who, at the time of their alleged commission of an offence (or act punishable under the criminal law), have not yet reached the age of 18 years. 37. The Committee wishes to remind States parties that they have recognized the right of every child alleged as, accused of, or recognized as having infringed the penal law to be treated in accordance with the provisions of article 40 of CRC. This means that every person under the age of 18 years at the time of the alleged commission of an offence must be treated in accordance with the rules of juvenile justice. 38. The Committee, therefore, recommends that those States parties which limit the applicability of their juvenile justice rules to children under the age of 16 (or lower) years, or which allow by way of exception that 16 or 17-year-old children are treated as adult criminals, change their laws with a view to achieving a non-discriminatory full application of their juvenile justice rules to all persons under the age of 18 years. The Committee notes with appreciation that some States parties allow for the application of the rules and regulations of juvenile justice to persons aged 18 and older, usually till the age of 21, either as a general rule or by way of exception. 39. Finally, the Committee wishes to emphasize the fact that it is crucial for the full implementation of article 7 of CRC requiring, inter alia, that every child shall be registered immediately after birth to set age-limits one way or another, which is the case for all States parties. A child without a provable date of birth is extremely vulnerable to all kinds of abuse and injustice regarding the family, work, education and labour, particularly within the juvenile justice system. Every child must be provided with a birth certificate free of charge whenever he/she needs it to prove his/her age. If there is no proof of age, the child is entitled to a reliable medical or social investigation that may establish his/her age and, in the case of conflict or inconclusive evidence, the child shall have the right to the rule of the benefit of the doubt. D. The guarantees for a fair trial 40. Article 40 (2) of CRC contains an important list of rights and guarantees that are all meant to ensure that every child alleged as or accused of having infringed the penal law receives fair treatment and trial. Most of these guarantees can also be found in article 14 of the International Covenant on Civil and Political Rights (ICCPR), which the Human Rights Committee elaborated and commented on in its general comment No. 13 (1984) (Administration of justice) which is