While demographic characteristics of sex workers vary by region and are hard to measure, some studies have attempted to estimate the composition of the sex work communities in various places.
For example, one study of sex work in Tijuana, Mexico found that the majority of sex workers there are young, female and heterosexual.
Such groups view prostitution variously as a crime or as victimization, and see the term "sex work" as legitimizing criminal activity or exploitation as a type of labor.
Sex workers may be any gender and exchange sexual services or favors for money or other gifts.
However, studies like this one can come under scrutiny for a perceived emphasis on the activities and perspectives of pimps rather than those of sex workers themselves.
Another criticism is that sex trafficking may not be adequately assessed in its relation to sex work in these studies.
Many of these studies attempt to use smaller samples of sex workers and pimps in order to extrapolate about larger populations of sex workers.
One report on the underground sex trade in the United States used known data on the illegal drug and weapon trades and interviews with sex workers and pimps in order to draw conclusions about the number of sex workers in eight American cities.Many studies struggle to gain demographic information about the prevalence of sex work, as many countries or cities have laws prohibiting prostitution or other sex work.In addition, sex trafficking, or forced sex work, is also difficult to quantify due to its underground and covert nature.Thus, although the term sex worker is sometimes viewed as a synonym or euphemism for "prostitute", it is more general.Some people use the term to avoid invoking the stigma associated with the word "prostitute".Depending on local law, sex workers' activities may be regulated, controlled, tolerated, or prohibited.