Young girls, not just women, are forced into prostitution in Tijuana and Juarez.

The Journal of the American Medical Association published a new study, "Sexual Violence and HIV Infection Associated With Adolescent vs. Adult Entry Into the Sex Trade in Mexico," which found that 1-in-4 sex workers in Juarez and Tijuana were forced into sex work while they minors, younger than 18. Furthermore, 1-in-8 sex workers were 15 years old or younger when they become participants in sex trade.

Prostitution isn't a field that exclusively employs fully consenting adults. In fact, in many nations, including Mexico, the exploitation of minors is a cornerstone of the seedy sex work market. Also, while it's typical to see girls who are 14 or older walking the streets of Tijuana, there are victims of sex trafficking who are as young 8 and 10 years old, who are sold by family members to earn a handful of cash.

Younger girls face increased risks of being forced into the sex industry because there's a greater value associated with young flesh. Young girls are easier to market, and buyers will pay more for them. They'll also spend top dollar on virgins, interested in paying for purity, innocence or quality. Approximately a third of girls younger than the age of 16 reported that condom usage wasn't allowed or was discouraged during the first month of "providing services," which boosts the likelihood of becoming infected with human immunodeficiency virus (HIV), STIs, or becoming pregnant. Minors face added risk of sexual violence, particularly Central American and Mexican youth migrating to the U.S., who face additional risk of being trafficked in the northern border cities of Mexico, according to the report.

Between March 2013 and January 2014, a team of researchers visited discotheques, street corners, massage parlors and public parks in Tijuana and Juarez to collect info underage female sex workers. More than 1,000 women were given $20 after completing a questionnaire that inquired about the age of induction into sex trade and similar questions.