Migrant sex work
Because of their illegal and vulnerable economic status, some migrant sex workers may find themselves in situations where coercion and forced sex work may be present. Under international legal definitions of human trafficking, forced and coercive forms of sex work are considered to be instances of involuntary sex trafficking. However, many scholars caution against categorizing sex workers as either completely voluntary or completely involuntary. They often argue that sex work, like other forms of labor, can span a spectrum between the two extremes, with most circumstances falling in the middle through various labor rights violations. Nevertheless, the vulnerability of migrant sex workers can make them susceptible to exploitative or coercive labor practices that can resemble or be human trafficking.
Trafficking of children
The Optional Protocol on the Sale of Children, Child Prostitution and Child Pornography is a protocol of the Convention on the Rights of the Child, formally adopted by the United Nations in 2000. Essentially, this protocol formally requires states to prohibit the sale of children, child prostitution, and child pornography. According to the International Labour Organization, sexual exploitation of children includes all of the following practices and activities: 
Though measuring the extent of this practice is difficult due to its criminal and covert nature, the International Labour Organization estimates that there are as many as 1.8 million children sexually trafficked worldwide, while UNICEF's 2006 State of the World's Children Report reports this number to be 2 million. The International Labour Organization has found that girls involved in other forms of child labour - such as domestic service or street vending - are at the highest risk of being pulled into commercial child sex trafficking. Likewise, Kendall and Funk justifies how “young girls age 12 and under are malleable and more easily trained into their prospective roles as prostitutes, and because virginity is highly prized by certain consumers willing to pay a premium” (31).A variety of sources, including the I.L.O, and scholars Erin Kunze and D.M. Hughes, also contend that the increased use and availability of the Internet has served as a major resource for traffickers, ultimately increasing the incidence of child sex trafficking. In fact, in 2009, Illinois Sheriff Thomas J. Dart sued the owners of Craigslist, a popular online classifieds website, for its "allowance" and "facilitation" of prostitution, particularly in children. In response to public and legal pressure, Craigslist has since blocked all access to its "Adult Services" section.