(CNN) -- The Justice Department announced Friday it is revising a decades-old definition of rape to expand the kinds of offenses that constitute the crime and for the first time, include men as victims.
Now, any kind of nonconsensual penetration, no matter the gender of the attacker or victim, will constitute rape -- meaning that attacks on men will be counted.
The crime of rape will be defined as "penetration, no matter how slight, of the vagina or anus with any body part or object, or oral penetration by a sex organ of another person, without the consent of the victim," a Justice Department statement said.
Attorney General Eric Holder said the new definition will lead to a more comprehensive reporting of rape in the FBI's annual compilation of crime statistics.
"These long overdue updates to the definition of rape will help ensure justice for those whose lives have been devastated by sexual violence and reflect the Department of Justice's commitment to standing with rape victims," Holder said. "This new, more inclusive definition will provide us with a more accurate understanding of the scope and volume of these crimes."
An FBI advisory panel recently recommended the revision to the antiquated definition, established in 1927.
The law then defined rape as "the carnal knowledge of a female, forcibly and against her will." That meant that it was only an act of rape if a man forcibly penetrated a woman through her vagina. It excluded oral and anal penetration; rape of males; penetration of the vagina and anus with an object or body part other than the penis; rape of females by females; and non-forcible rape.
Under the old definition, the case of former Penn State assistant coach Jerry Sandusky -- charged with 40 counts in what authorities allege was the sexual abuse of young boys -- would not be considered as rape.
"Needless to say we are very pleased that the FBI has agreed to revise its definition used in data collection so it more accurately reflects what the public understands to be rape and what our current criminal statutes say," said Carol Tracy, executive director of the Women's Law Project, which has been pushing for the definition change.
The revised definition includes any gender of victim or perpetrator. It also includes instances in which a victim is incapable of giving consent because of mental or physical incapacity, such as intoxication. Physical resistance is not required to demonstrate lack of consent.
At issue here is how the old definition of rape affected the FBI's Uniform Crime Reporting system.
Tracey and other advocates, as well as law enforcement officials, have said that the old definition led to under-reporting of rape. That in turn shaped public perceptions of the prevalence of rape and affected federal funding for resources in combating the crime.
Justice and FBI officials said, however, that it could take several years for all 18,000 of the nation's police agencies to report rape under the new definition.
All reporting to the Uniform Crime Report is voluntary, and state legal codes, resources, and technical capabilities vary widely. Although top officials expect reported forcible rapes eventually to increase from the 84,767 reported in 2010, they declined to offer any estimate of the statistics to be issued for 2011.
"This change will give law enforcement the ability to report more complete rape offense data, as the new definition reflects the vast majority of state rape statutes," said David Cuthbertson, assistant director of the FBI's Criminal Justice Information Services.
"As we implement this change, the FBI is confident that the number of victims of this heinous crime will be more accurately reflected in national crime statistics," he said.
In 2010, the last year for which a final report is available, the FBI reported a forcible rape every 6.2 seconds. With a broader definition, that statistic will probably be even more grim, said Mai Fernandez, executive director of the National Center for Victims of Crime.
"The problem is much greater than what you have been previously seeing," she said. "You don't really know what the problem is. Therefore, you can't really create solutions to fit."
The push for a revision started with the Women's Law Project over a decade ago. Tracey had a letter written to FBI Director Robert Mueller that was slated to be mailed on September 11, 2001.
The terrorist attacks that day changed everything. The FBI's attention turned to other pressing issues.
Last year, Tracy testified before a congressional committee looking at the failures of police departments to thoroughly investigate rape. She said then that an antiquated, narrow definition of rape was a harmful disservice to countless victims.
Friday, she thanked Justice and White House officials who listened. Among them was Vice President Joe Biden, author of the Violence Against Women Act.
"Rape is a devastating crime and we can't solve it unless we know the full extent of it," Biden said Friday. "This long-awaited change to the definition of rape is a victory for women and men across the country whose suffering has gone unaccounted for over 80 years."
Kim Gandy, vice president of the Feminist Majority Foundation, called the revision a "major policy change" that "will dramatically impact the way rape is tracked and reported nationwide."
Tracey, however, noted that the change is about data collection and that America has a long way to go in tackling rape.
"We still need to improve police practices and rid society of the stereotypes about rape victims," she said. "This is one important change but not the only change that's needed."
CNN's Terry Frieden contributed to this report.