In some cultures, concubines and their children had distinct rights and legitimate social positions.
The Vienna Declaration and Programme of Action calls for an international effort to eradicate sexual slavery as an abuse of human rights.
The terms "forced prostitution" and "enforced prostitution" appear in international and humanitarian conventions but have been insufficiently understood and inconsistently applied.
"Forced prostitution" generally refers to conditions of control over a person who is coerced by another to engage in sexual activity.
The report lists Thailand, China, Nigeria, Albania, Bulgaria, Belarus, Moldova and Ukraine as major sources of trafficked persons.
Commercial sexual exploitation of children (CSEC) includes child prostitution (or child sex trafficking), child sex tourism, child pornography, or other forms of transactional sex with children.
The BBC News cited a report by UNODC as listing the most common destinations for victims of human trafficking in 2007 as Thailand, Japan, Israel, Belgium, the Netherlands, Germany, Italy, Turkey and the US.
The law in Sweden, Norway and Iceland – where it is illegal to pay for sex, but not to sell sexual services – is based on the notion that all forms of prostitution are inherently exploitative, opposing the notion that prostitution can be voluntary.
In contrast, prostitution is a recognized profession in countries such as the Netherlands and Germany.
In contrast to the crime of rape, which is a completed offence, sexual slavery constitutes a continuing offence. Forms of sexual slavery can, for example, be practices such as the detention of women in "rape camps" or "comfort stations", forced temporary "marriages" to soldiers and other practices involving the treatment of women as chattel, and as such, violations of the peremptory norm prohibiting slavery.
Sex trafficking is a type of human trafficking involving the recruitment, transportation, transfer, harbouring or receipt of people, by coercive or abusive means for the purpose of sexual exploitation.