Among other provisions, it requires equal treatment before all tribunals, agencies and bodies involved in the administration of justice, without distinction as to race, colour, or national or ethnic origin. Convention on the Elimination of All Forms of Discrimination against Women 33. Upon entry into force in September 1981, the Convention on the Elimination of All Forms of Discrimination against Women became the principal international instrument addressing discrimination against women in the political, economic, social, cultural and civil fields. The Convention currently has 173 States parties, which are required to undertake specific action in each of those fields to end discrimination against women and to allow them to exercise and enjoy human rights and fundamental freedoms on a basis of equality with men. 34. In addition, General Recommendation No. 19 on violence against women, adopted by the Committee on the Elimination of Discrimination against Women at its eleventh session, in 1992, is relevant to this Manual. It addresses gender-based violence, which impairs or nullifies the enjoyment by women of human rights and fundamental freedoms under general international law or under human rights conventions, as discrimination within the meaning of article 1 of the Convention. Furthermore, General Recommendation No. 19 provides that gender-based violence may breach specific provisions of the Convention, regardless of whether those provisions expressly mention violence. Convention on the Rights of the Child 35. The Convention on the Rights of the Child entered into force in September 1990 and currently has 191 States parties. It provides for certain special rights for juvenile offenders, in recognition of their special vulnerability and society's interest in rehabilitating them. In particular, article 37 of the Convention sets out a prohibition on life imprisonment of juveniles, as well as protecting them against capital punishment. Imprisonment of juveniles must be a measure of last resort and, when imposed, must be for the shortest appropriate period of time. Article 37 further requires States parties to ensure that no child is subjected to torture or other cruel, inhuman or degrading treatment or punishment. In every case, article 37 requires that juveniles in conflict with the law be treated with humanity and respect for the dignity of the human person, and in a manner which takes into account their age. In this regard, every child deprived of liberty shall be separated from adults unless it is considered in the child's best interest not to do so. Detained children shall also have the right to maintain contact with their family through correspondence and visits, save in exceptional circumstances. Article 40, paragraph 1, underlines the desirability of promoting a child's reintegration and assuming a constructive role in society. Optional Protocol to the Convention on the Rights of the Child on the sale of children, child prostitution and child pornography 36. The Optional Protocol to the Convention on the Rights of the Child on the sale of children, child prostitution and child pornography, which entered into force in January 2002 and currently has 51 States parties, is also relevant to this Manual. 12