CRC/C/CHN/CO/3-4 relating to sexual abuse and exploitation is effectively enforced, and that perpetrators of such crimes are brought to justice with sanctions proportionate to their crimes; (b) The State party to systematically collect data on sexual exploitation and abuse of girls and boys, on the number of investigations and penalties against perpetrators, and on redress and compensation offered to the victims; (c) Mainland China, Hong Kong, China and Macao, China to establish effective and child-friendly procedures and mechanisms, including free helplines accessible to children, to receive, monitor and investigate complaints; and to undertake awareness-raising activities among children, including among boys, to encourage the reporting of sexual violence and abuse in schools and communities; (d) Hong Kong, China to conduct a comprehensive review of sexual offences covered in the Crimes Ordinance and reform laws to criminalize all forms of child pornography and sexual exploitation of children on the Internet; it should also establish effective policies and procedures to identify and support child victims of trafficking and sexual exploitation; (e) Hong Kong, China and Macao, China, respectively, to develop a strategy to respond to the shelter, health, legal and psychosocial needs of child victims of sexual exploitation and abuse, including through adequate training for professionals. Freedom of the child from all forms of violence 47. Recalling the recommendations of the United Nations study on violence against children (A/61/299), the Committee recommends that the State party prioritize the elimination of all forms of violence against children. The Committee further recommends that the State party take into account its general comment No. 13 (2011), and in particular: (a) Develop a comprehensive national strategy to prevent and address all forms of violence against children; (b) Adopt a national coordinating framework, including mandatory reporting of all cases and the follow-up measures necessary to address all forms of violence against children; (c) Pay particular attention to and address the gender dimension of violence; (d) Cooperate with the Special Representative of the Secretary-General on violence against children and other relevant United Nations institutions. E. Family environment and alternative care (arts. 5, 18 (paras. 1–2), 9–11, 19-21, 25, 27 (para. 4) and 39 of the Convention) Family environment 48. The Committee notes with concern that due to the restrictive hukou policy, many migrant parents face the difficult choice of leaving their children behind, resulting in 55 million children growing up without one or both parents in rural mainland China. In this regard, the Committee expresses concern that instead of tackling the root causes of abandonment of children, the State party continues to adopt policies that often promote institutionalization of left-behind children, including in boarding schools. 49. In accordance with article 9 of the Convention, the Committee urges the State party to take immediate measures to avoid the separation of children from the family environment, including by abolishing the hukou system and providing appropriate 11