89. Establishing, registering and documenting a child’s nationality and birth is critical because it provides grounds for the child to secure other rights, such as health care, education, freedom of movement and protection in the labour market. A lack of documented nationality could also result in prolonged detention in immigration facilities, among others, which should be avoided, as it is never in the best interests of the child.158 Documented and registered age also determines treatment by the justice system by establishing that a child is below the minimum age of criminal responsibility or under 18 and therefore subject to lower penalties and treatment according to juvenile justice standards.159 Consequently, denying a child the right to birth registration or nationality renders him or her vulnerable to a multiplicity of human rights violations. Indeed, the Committee on the Rights of the Child has found that the failure to provide a child with birth registration or other identification documents constitutes neglect of the child, exposing them to potentially vulnerable situations.160 denied nationality because the link to the parent who is a national is not recognized, States should adopt a flexible approach to the acceptance of evidence of that link, taking into account the specific context, including by facilitating the provision of documents and consular services to assist nationals with the registration of their child born abroad and with recognition of their nationality. The fact that birth registration, which establishes the place of birth and parents of a child, has been conducted by a non-State actor that is not recognized as legitimate should not stand in the way of the recognition of the parent–child relationship for which the registration is evidence. States should take actions to speedily establish or not unduly delay the recognition of nationality, because of the impact that such a delay can have on the child’s enjoyment of other rights and on their sense of identity.161 90. In relation to recognition of nationality ofchildren affected by the foreign-fighter phenomenon, States should refrain from applying their own nationality rules in an arbitrary or discriminatory fashion. Denying a child nationality because of the association with a parent who is deemed to be a foreign fighter would be contrary to the non-discrimination principle under the Convention on the Rights of the Child (article 2) and the best interests of the child (article 3) (see chapter 1 on the principles). When a child is 158 Committee on the Elimination of All Forms of Discrimination against Women, general recommendation No. 32 (2014), on the gender-related dimensions of refugee status, asylum, nationality and statelessness of women, para. 57. 159 Committee on the Rights of the Child, general comment No. 24 (2019), para 39. 160 Committee on the Rights of the Child, general comment No. 13 (2011), para 72(g). 161 European Court of Human Rights, Mennesson v. France (65192/11), judgment of 26 June 2014, para. 97 in which the court says that children whose legal relationship with their parent is not established “face a worrying uncertainty as to the possibility of obtaining recognition of French nationality under Article 18 of the Civil Code ... That uncertainty is liable to have negative repercussions on the definition of their personal identity” (emphasis added). 41.