Keyvette Gamble went to a friend’s house with her 4-year-old daughter, playing cards into the early morning with plans to spend the night at the Southwest Washington apartment. After everyone had nodded off, Gamble slipped over to a bed where her friend’s 14-year-old son was sleeping.

Gamble, 24, then sexually assaulted the teenage boy, according to court records. The attack in September was one of three child sex abuse cases to reach a D.C. courtroom this year that involved an adult female defendant accused of sexually assaulting a teenage boy.

While sex abuse cases are all too common, prosecutors and child victim advocates say prosecutions of adult women sexually attacking boys are extremely rare. All unrelated, the three cases in the District surprised local authorities and have raised awareness of an often-underreported crime.

“This is unusual,” said prosecutor Kelly Higashi, chief of the sex offense and domestic violence section of the D.C. Superior Court unit for the U.S. attorney’s office. “People do not often recognize the harm this does to a boy.”

Teenage boys rarely report such attacks to police or to close family members, authorities said. The boys keep the abuse quiet, either out of guilt or, in some cases, because they believe such incidents are a rite of passage to adulthood.

Child welfare advocates say there is a double standard that makes it more difficult to identify cases involving adult female attackers and young male victims.

“If you put a teenage girl in the same situation and the abuser is a male, you will have an entirely different reaction from society,” said Deborah Donavan Rice, executive director of Stop it Now, a Northampton, Mass.-based child sex abuse prevention group. “But child sexual abuse is child sexual abuse.”

It is difficult to determine how often boys are sexually assaulted by women. One group, the National Center for Post Traumatic Stress Disorder, estimates that instances involving female offenders and male juvenile victims make up less than 14 percent of sex abuse cases nationwide. Other groups say such cases are less common. Still, advocates say, parents of boys who are victims are becoming more likely to report such crimes, and authorities are prosecuting them more aggressively.

Christopher Mallios of Aequitas, a District-based sex-crime victim advocacy group, said during his 16 years as a Philadelphia prosecutor he had seen police and prosecutors “high-five” teenage boys who had been sexually assaulted by women, saying that the boys were “lucky.”

Mallios said that view — that teenage male victims should not being taken seriously — is slowly being eradicated. “It’s rape because the law says it is rape,” he said. “Minors legally cannot consent to sex with adults.”

D.C. sex crime prosecutor Higashi said it is often adults close to the victims who coax them into talking about the abuse and to come forward, and she praised adults in the D.C. cases for being willing to support the children involved. It is often because boys feel uncomfortable talking about what happened that leads them to keep silent, she said.

“The adult’s reaction often impacts the child’s reaction,” Higashi said.

Such were the circumstances with Gamble. Charges against her came after the 14-year-old victim told an adult about it.

In that incident, Gamble took advantage of her friend’s son, in her friend’s apartment, according to court records. When Gamble went to the boy, the teenager reached for a condom and then was sexually assaulted in his own bed.

Last week, Gamble, standing before a D.C. Superior Court judge and wiping tears from her eyes, pleaded guilty to one count of first-degree child abuse. She faces a maximum of 15 years in prison when she is sentenced in October. At the hearing, Judge William M. Jackson encouraged Gamble to make “contingency plans” for the long-term care of her two children, a 4-year-old daughter and a 3-month-old infant, by the time she returns to court for sentencing.

All three D.C. cases involved women who were friends of the victim’s family. In the case of Zakiya Gaskins — a Southwest Washington woman charged with sexually assaulting her neighbor’s 13-year-old son in January — authorities had to relocate the teenager and his family because neighbors harassed him after he told his mother that his friend’s mother had sexually assaulted him.

“People were teasing him, asking if he was a ‘punk,’ and what’s wrong with him and why he didn’t like it,” said an official who spoke on the condition of anonymity because the case is still open.

Gaskins allegedly attacked the boy when he was spending the night with her 13-year-old son at her apartment, a night that was supposed to be filled with video games, prosecutors said.

The woman gave the teenager a glass of fruit juice mixed with vodka, according to court records. Later that evening, according to court records and testimony from a D.C. detective, Gaskins pulled the teenager into her bedroom and sexually assaulted him. Gaskins’s children banged on her bedroom door, crying for their mother to “let him go,” according to court records. When Gaskins fell asleep, the teen fled her bedroom.

At the hearing on Aug. 20, a soft-spoken Gaskins, with her ankles and wrists in shackles, denied forcing the teenager to touch her sexually, but admits the teen did touch her. Gaskins’s attorney, Kevin McCants, said his client was drunk at the time of the incident and unsuccessfully tried to stop the teen from touching her.

Gaskins, 32, pleaded guilty to one count of first-degree child sexual abuse, entering an Alford plea, meaning she admitted there was enough evidence to convict her but not conceding that she committed the crime. She is scheduled for sentencing in November and could face about 7½ years in prison.

Gaskins’s three children, who are 13, 9 and 4, live with her mother. Beck ordered Gaskins to remain in D.C. jail until her sentencing. She also will have to register as a child sex offender.

In the third recent case, Heaven Wright, 18, of Northwest Washington, was sentenced in August to serve 180 days in prison after she pleaded guilty to sexually assaulting a 13-year-old last summer. Authorities learned of the attack after the teenager’s mother took the boy to a hospital, where he tested positive for a sexually transmitted disease. Wright, according to court records, later admitted to police that she had a sexual relationship with the boy and knew his age. The two, who had known each other for a year, had three separate sexual encounters, according to court records.

“People need to realize these types of cases do happen,” Higashi said. “They are more rare, but they happen.”

Magda Jean-Louis contributed to this report.