I can't speak for how their "sexual assault" criterion is defined in the article, but as for the "rape" statistic, note that most western countries define rape for reporting purposes as "forced penetration", specifically excluding "forced envelopment" from the statistic, and thereby excluding practically all male rape victims with female perpetrators from crime statistics.

For example, here are the statistics for sexual violence in the year 2011, according to the CDC (note that there's also a 2013 CDC report with effectively the same numbers for the US):

an estimated 1.6% of women reported that they were raped in the 12 months preceding the survey. The case count for men reporting rape in the preceding 12 months was too small to produce a statistically reliable prevalence estimate.

And

The percentages of women and men who experienced these other forms of sexual violence victimization in the 12 months preceding the survey were an estimated 5.5% and 5.1%, respectively.

Added together, we see that 7.1% of women and 5.1% of men reported being victims of sexual violence in 2011. That is, 58% of victims of all sexual violence in 2011 were women, and 42% were men. For every 3 female victims, there were 2 male victims.

Now on to the cited claim that "99% of rape perpetrators are men". From the "Characteristics of Sexual Violence Perpetrators" section about a third of the way down, keeping in mind the percentages above:

For female rape victims, an estimated 99.0% had only male perpetrators (more on this later...). In addition, an estimated 94.7% of female victims of sexual violence other than rape had only male perpetrators.

And

For male victims, the sex of the perpetrator varied by the type of sexual violence experienced. The majority of male rape victims (an estimated 79.3%) had only male perpetrators. For three of the other forms of sexual violence, a majority of male victims had only female perpetrators: being made to penetrate (an estimated 82.6%), sexual coercion (an estimated 80.0%), and unwanted sexual contact (an estimated 54.7%). For noncontact unwanted sexual experiences, nearly half of male victims (an estimated 46.0%) had only male perpetrators and an estimated 43.6% had only female perpetrators.

To help us with the breakdowns of these numbers, earlier in the report we find that:

1.7% of men were made to penetrate a perpetrator in the 12 months preceding the survey [and] an estimated 1.3% of men experienced sexual coercion in the 12 months before taking the survey [and] an estimated 1.6% of men having experienced unwanted sexual contact in the 12 months before taking the survey [and] an estimated 2.5% of men experienced this type of victimization (noncontact unwanted sexual experiences) in the previous 12 months

So, of the 1.7% of made to penetrate male victims, 82.6% of perpetrators were female. Of the 1.3% sexual coercion, 80% of perpetrators were female. Of the 1.6% unwanted sexual contact, 54.7% were female, and of the 2.5% noncontact, 43.6% were female.

So, 1.4% of the 1.7% made to penetrate, 1% of the 1.3% sexual coercion, .9% of the 1.6% unwanted sexual contact, and 1.1% of the 2.5% noncontact.

So, 4.4% of the 7.1% of men reporting sexual violence had female perpetrators. That is, 62% of sexual violence against men is committed by women (in 2011).

So, going back to our numbers above, we see that 62% of the 42% of sexual violence with men as victims was committed by women.

Our final numbers are: 74% of sexual violence in total in the US is committed by men, and 26% is committed by women. Which ain't great, but that feels a lot more realistic than "99%", and it's a far cry from the intentionally misleading numbers the "article" is citing.

BUT IT GETS WORSE...

What happens when we look at just rape? Note that first we have to figure out what the CDC means by "rape", because at first "99% of rape is committed by men" looks pretty damning.

Well, "rape" is defined by the CDC for the purposes of this study as "completed or attempted forced penetration or alcohol- or drug-facilitated penetration". That is, only being penetrated counts as rape.

Men, on the other hand, get the completely separate category "made to penetrate", that is, "being forced to have sex with someone, just doing the penetrating instead of being penetrated."

So, 99% of rapists are men because rape is intentionally defined as "being penetrated" to exclude male victims of rape and female perpetrators of rape from the statistics.

Well, what happens when we actually look at those numbers, counting "made to penetrate" as, y'know, rape, because it is rape?

an estimated 1.6% of women (or approximately 1.9 million women) were raped in the 12 months before taking the survey

And

The case count for men reporting rape in the preceding 12 months was too small to produce a statistically reliable prevalence estimate.

Which is, again, because male rape victims are effectively excluded from this definition. Also, we have this:

an estimated 1.7% of men were made to penetrate a perpetrator in the 12 months preceding the survey

And

Characteristics of Sexual Violence Perpetrators For female rape victims, an estimated 99.0% had only male perpetrators. In addition, an estimated 94.7% of female victims of sexual violence other than rape had only male perpetrators. For male victims, the sex of the perpetrator varied by the type of sexual violence experienced. The majority of male rape victims (an estimated 79.3%) had only male perpetrators. For three of the other forms of sexual violence, a majority of male victims had only female perpetrators: being made to penetrate (an estimated 82.6%), sexual coercion (an estimated 80.0%),

Note that these numbers clearly show that made to penetrate happens just as much each year as "rape". This means that fully half of rape victims are men (in 2011 - the number fluctuates in the other years of the study, but not more than 5%).

Finally, if 99% of rapists are men and 83% of an equal number of "made to penetrators" are women ... then an estimated 42% of the perpetrators of nonconsensual sex (that is, rape) in 2011 were women.

Sorry for the wall of text, but I think it's important to debunk this sort of blatantly biased misinformation. As feminists we should care about all victims of rape, and shouldn't create intentionally biased categories to create false narratives about perpetrators, or, more importantly, to exclude valid categories of victims who need our help.

Incorrect