A/HRC/17/33 to address irregular migration by strengthening border controls and criminalizing both the facilitators and the migrants themselves. The Special Rapporteur has shown in the course of his mandate that the use of criminal measures to manage migration undermined the human rights of migrants and curtailed their access to basic social rights, particularly health care, education and housing. B. Protection of children in the context of migration 26. The Special Rapporteur also focused on the protection of children in the context of migration, recalling the obligation of the State to ensure the protection of all children in all stages of the migration process.3 He presented an overview of the international legal framework applicable, proposed a conceptual framework and referred briefly to three categories of children affected by the migration process: those left behind by migrating family members; migrant children moving across borders; and migrant children in host countries. 27. Children have always been part of migration and affected by it in different ways. Children left behind by migrant family members are affected by migration in countries of origin. Children on the move are affected at the pre-departure stage in countries of origin and in countries of transit and destination at the passage and arrival stages. Children in host countries are affected at the post-arrival and long-term stay and integration stages of the migration process. Children move across borders with their parents or are accompanied by extended family members or other adults and within mixed migratory flows. Children are also increasingly seeking migration opportunities to move across borders unaccompanied, falling prey to organized crime and exploitation including smuggling, trafficking and contemporary forms of slavery. 28. The term “children left behind” refers to children raised in their home countries or in their countries of habitual residence who have been left behind by adult migrants responsible for them. The impact of migration on children left behind was difficult to measure. Many factors played a role in assessing how migration may affect the rights of children left behind. The inclusion of measures to promote family unity and facilitate the reunion of children with their parents in host countries was also necessary to address adequately the special needs and protection of children left behind. Many parents and other family members initially migrated without children, but subsequently planned to bring them to a host country. 29. Children on the move are migrant children taking an active part in the migration process, particularly at the passage and arrival stages in countries of transit and destination. They may be found migrating with their family members or independently, to seek opportunities for both education and employment. Children may also be forcibly on the move, such as when falling prey to transnational organized crime and exploitation networks. Unaccompanied and separated children on the move faced greater vulnerabilities and risks, including discrimination, sexual and other forms of violence. Frequent human rights issues affecting children on the move also included deportation and repatriation. Children should be repatriated only if it is in their best interest, namely, for the purpose of family reunification and after due process of law. Another major concern related to the particular vulnerability of children who were unaccompanied, undocumented and/or entering countries irregularly, including within mixed migratory flows, to unlawful or arbitrary deprivation of liberty. 3 See A/HRC/11/7. 7