It’s difficult to fathom that a sex act between an adolescent girl and a grown man would land the child in jail, but it happens every day on the streets of New York. Much time and effort is spent combating the sexual exploitation of children and the trafficking of foreign girls in our country, but young Americans who are trapped or tricked into prostitution often find themselves facing either jail time or further abuse.

These girls are the subject of David Schisgall and Nina Alvarez’s documentary “Very Young Girls,” which opens at IFC Center on Friday. Following various women and girls as they recount their past and present involvement in the sex trade, “Very Young Girls” explores a loophole in the justice system that is frequently exploited for profit. According to the law, underage girls are protected from adult men trying to have sex with them; but if money is exchanged, they are held quite accountable.

In “Very Young Girls,” one mother’s complaint gets to the heart of the matter: “Instead of taking her to the hospital,” she laments, “they took her to the jailhouse.” After her child was kidnapped and forced into prostitution, she escaped the control of her pimp only to be taken into police custody and charged with prostitution. Luckily, she avoided prison with a chance to rehabilitate at Rachel Lloyd’s nonprofit group GEMS (Girls Educational and Mentoring Services).

The film spends a good deal of time with Ms. Lloyd, a former prostitute herself, who founded GEMS in 1998 to help girls get out of “the life.” As we watch Ms. Lloyd reach out to these girls, it is fascinating to see the rationalizations they employ to explain away their abuse. By and large, they are drawn less to the money or power they earn than to the attention their pimps lavish upon them. Many horror stories are told here, but the most frequent and striking are those in which the girls can’t ignore the feelings they still have for men who abused, beat, and tricked them into selling their bodies. Even as the girls describe these abusers as their boyfriends and lovers, they mention how they were told not to come home if they didn’t have sex with other men. Between beatings, exploitation, and mental abuse, these pimps knew what their girls wanted — someone to tell them they were loved.

As she accepts the 2006 Reebok Human Rights Award at one point in the film, Ms. Lloyd takes the opportunity to reprimand the Academy of Motion Picture Arts and Sciences for bestowing the hip-hop group Three 6 Mafia with an Oscar for “It’s Hard Out Here for a Pimp,” its theme to the film “Hustle and Flow.” The directors of “Very Young Girls” further underline the strange dichotomy between disdain and objectification by airing some home video footage shot by two pimps who envisioned that it would be great fodder for a television series. Instead it was great fodder for the police, who put them in jail for 10 years.

But the disgusting pride they felt in documenting their abuse of women is a disturbing aspect of the sex trade. Despite today’s discussions of personal freedom and self-empowerment for women in the sex industry, it is hard to ignore the abject manipulation that is an intrinsic part of any attempt to make a business out of selling sex for profit. The average age of entry for sex workers is 13 years old. As “Very Young Girls” shows, there is something very wrong at work here. And it’s not going away.