(CNN) In the age of #MeToo , who's getting treated more unfairly: men or women?

To hear President Donald Trump tell it, "It is a very scary time for young men in America."

"It's a very scary situation where you're guilty until proven innocent," Trump said about sex assault claims against men, including against his Supreme Court nominee Brett Kavanaugh

"You could be somebody that was perfect your entire life, and somebody could accuse you of something."

Trump isn't alone in his concern. Many women, including mothers of boys, are using the hashtag #ProtectOurBoys to denounce what they consider false claims.

But those appear to be anomalies. Studies suggest the prevalence of false reporting on sexual assault is between 2% and 10% , according to the National Sexual Violence Resource Center.

And there's a big caveat to those numbers: "Research shows that rates of false reporting are frequently inflated, in part because of inconsistent definitions and protocols," the resource center said.

For example, some law enforcement agencies might label a rape claim as "false" just because there's not enough corroborating evidence to prosecute. (Those cases would be more accurately described as "baseless" rather than "false.")

"It does not mean that some form of sexual assault may not have occurred, but only that from the legal perspective ... the case does not meet the legal criteria, or it is 'baseless,'" the resource center said.

The FBI and the International Association of Chiefs of Police have tried to improve accuracy when it comes to labeling sex assault claims.

They issued guidelines saying certain factors shouldn't be sole reasons for labeling a report "false," such as:

-- Delayed reporting

-- Insufficient evidence to prosecute

-- A victim's decision to not cooperate with investigators

-- Inconsistencies in a victim's statements

But those are just guidelines, not rules.

"While some police departments may follow these guidelines, it is not mandatory, and as a result, many do not," the sexual violence resource center said.

And that can lead to more "false" claims than there actually are.

Another reason why sex assault cases can be perceived as false is the frequent lack of witnesses.

Offenders "are deliberate and strategic about not having witnesses. This is intrinsic to the crime," said Kristen Houser, spokeswoman for the National Sexual Violence Resource Center.

"So, if our nation continues to demand that there be witnesses, we are essentially ignoring the very nature of the crime."