to women and girls, as men and boys can also be subject to gender-based violence associated with trafficking.185 In order to qualify for refugee status, an individual’s “well-founded fear of persecution” must relate to one or more of the grounds specified in the definition contained in the Refugee Convention, namely “race, religion, nationality, membership of a particular social group or political opinion”. It is sufficient for the ground to be a relevant factor contributing to the persecution, and it does not need to be the sole or even dominant cause.186 The UNHCR has noted the possibility that a number of grounds included in the Convention are being used by traffickers to target and select victims of trafficking. For example, members of a particular race or ethnic group may be especially vulnerable to trafficking as a result of conflict, owing to specific market demands187 and/or because they may be less effectively protected by authorities in the country of origin.188 In order to make a positive determination of the risks facing an individual owing to her or his “membership of a particular social group”, it is first necessary to demonstrate that members of this group share innate and unchangeable characteristics (other than being persecuted) and that they are generally recognized as a group.189 However, not all members of the social group need to be at risk of persecution: it is sufficient to show that the claimant’s well-founded fear of persecution is based on her or his membership of that group.190 Women, men and children (as well as subsets of these groups, such as unaccompanied children) may constitute particular social groups for the purposes of refugee status determination. As such, the fact of belonging to one of these groups might contribute to an individual’s fear of being subject to persecution, including sexual exploitation, through trafficking.191 Former victims of trafficking might also be considered as constituting a social group for whom future persecution could involve reprisals, punishment and ostracism,192 provided that they either share a common characteristic other than the risk of being persecuted or are perceived as a group by society.193 The final criterion, the “absence of effective state protection”, requires that a decision be made as to whether or not the state is willing and able to protect returning victims from feared persecution. This depends on a range of factors, the most important of which being whether mechanisms are in place to prevent and combat trafficking, and whether such mechanisms are being effectively implemented. The UNHCR Trafficking Guidelines state that where a “State fails to take such reasonable steps as are within 185  See also UNHCR Guidelines on International Protection No. 9, para. 14. 186  UNHCR Trafficking Guidelines, para. 29. 187  UNHCR Trafficking Guidelines, paras. 32 and 34. 188  UNHCR Trafficking Guidelines, para. 32. 189  UNHCR Trafficking Guidelines, para. 37. See also UNHCR Guidelines on International Protection No. 2. 190  UNHCR Guidelines on International Protection No. 2, para. 17 191  UNHCR Trafficking Guidelines, para. 38. 192  Ibid., para. 39. 193  Ibid., para. 37. 64 Part 2: Explanatory Report to the Principles