A/HRC/31/37 Social and Cultural Rights has stated that the concept of family must be understood in a wide sense and in accordance with appropriate local usage. 22 Other international human rights mechanisms have expressed similar views.23 25. The concept of family may also differ according to the specific rights and responsibilities at stake. For instance, in relation to the rights of the child, the concept of family may include a variety of arrangements that can provide for a young child’s care, nurturance and development, including the nuclear family, the extended family and other traditional and modern community-based arrangements, provided these are consistent with the rights and the best interest of the child.24 Likewise, the notion of “family environment” may encompass children’s social ties in a wider sense. 25 The International Convention on the Protection of the Rights of All Migrant Workers and Members of Their Families defines “members of the family” as persons in a relationship that, under applicable law, produces effects equivalent to marriage, as well as their dependent children and other dependent persons recognized as such by applicable legislation (arts. 4 and 44 (2)). 26. States retain some leeway in defining the concept of family in national legislation, taking into consideration the various legal systems, religions, customs or traditions within their society, including indigenous and minority cultures.26 However, international standards set forth at least two minimum conditions for the recognition and protection of families at the national level: first, respect for the principle of equality and nondiscrimination, including the equal treatment of women; and second, the effective guarantee of the best interest of the child.27 Given those parameters, human rights mechanisms have found that some forms of relationships, such as polygamy and child marriage, are contrary to international human rights standards and should be prohibited. 28 27. In addition to the above principles, international mechanisms have called upon States to protect specific forms of the family in view of the vulnerability of their members in relation to the enjoyment of human rights. For instance, attention has been drawn to the discrimination suffered by women and children in de facto unions and there have been calls for the regulation of those unions in domestic law. 29 In similar terms, the Committee on 22 23 24 25 26 27 28 29 8 See Committee on Economic, Social and Cultural, general comment No. 4 (1991) on the right to adequate housing, para. 6; and general comment No. 5 (1994) on persons with disabilities, para. 30. See Committee on the Elimination of Discrimination against Women, general recommendation No. 21 (1994) on equality in marriage and family relations, paras. 13 and 18; and general recommendation No. 29 (2013) on the economic consequences of marriage, family relations and their dissolution, para. 24; Committee on the Rights of the Child, general comment No. 7 (2005) on implementing child rights in early childhood, para. 15; also A/HRC/29/40, paras. 23-24. See Committee on the Rights of the Child, general comment No. 7, para. 15. See Committee on the Rights of the Child, general comment No. 14 (2013) on the right of the child to have his or her best interests taken as a primary consideration, para 70. See Human Rights Committee, general comment No. 16 (1988) on the right to privacy, para. 5; and CCPR/C/60/D/549/1993/Rev.1, para. 10.3. See International Covenant on Civil and Political Rights, art. 23(4); International Convention on the Elimination of All Forms of Discrimination against Women, arts. 2 and 5 (b); and Convention on the Rights of the Child, art. 18 (1). See Joint general recommendation No. 31 of the Committee on the Elimination of Discrimination against Women/general comment No. 18 of the Committee of the Rights of the Child (2014) on harmful practices, paras. 24-26. See Committee on the Elimination of Discrimination against Women, general recommendation No. 29, paras. 30-31; also A/HRC/29/40, para. 74 (c).