In this week’s issue of the National Review, Kevin Williamson accuses actress and screenwriter Lena Dunham of sexually abusing her little sister when Dunham was a child. It’s “the sort of thing that gets children taken away from non-millionaire families without Andover pedigrees and Manhattanite social connections,” he writes. The evidence of this abuse, he says, comes directly from Dunham’s new memoir, Not That Kind of Girl, in which she describes masturbating next to her six-years-younger sister, bribing her sister to kiss her, and looking inside her sister’s vagina.

Williamson hardly has the authority to call this behavior sexual abuse—a claim that should not be thrown around lightly. Not only does he not have a background in human sexuality or child psychology, but it also seems he didn’t consult with anyone who does, or he would have quickly learned that Dunham’s behavior as a youngster was normal. “This is clearly not a case of abuse,” says developmental psychologist Ritch Savin-Williams, director of the Sex and Gender Lab at Cornell University. “Children have been doing this stuff forever and ever and ever and ever, and they will do it forever and ever and ever.”

Let’s start with the episode for which Williamson says “there is no non-horrific interpretation”: when Dunham approached her 1-year-old sister, Grace, and, as she writes, “leaned down between her legs and carefully spread open her vagina.” According to the American Academy of Pediatrics, touching and looking at new sibling’s genitals is a “normal, common” behavior in kids ages 2 to 6. (Yes, Dunham was apparently 7 when it happened, but still.) This was happening between sisters, too, which is important. It’s not necessarily OK for a child to play sexually with a younger child if he or she don’t typically play together, but among siblings or close friends it can be different. Sexual play often arises naturally out of pretend play, in part because, psychologists have theorized, friends and siblings become curious about each other’s body parts. Indeed, Dunham doesn’t describe trying to play with her sister’s vagina; she just wanted to see what it looked like.

Williamson says that Dunham also admits to, in his words, “casually masturbating while in bed next to her younger sister.” According to Dunham, her sister was the one crawling into her bed, and Grace was asleep when the masturbation happened—so Dunham, who was at least 13 at the time, was essentially masturbating in private. Masturbation is, of course, very normal: A 2011 study conducted by researchers at the University of Indiana School of Medicine reported that nearly half of 14-year-old girls masturbate. In fact, the paper called masturbation “integral to normal sexual development.” Hell, one survey found that two-thirds of professionals think it’s normal for 3-year-olds to masturbate.

Then there is Dunham’s admission that she bribed her sister to kiss her on the lips for five seconds. Yes, it’s coercive—but is it harmful? “It sounds, from what Dunham is writing, that it’s just playful activity. One would seriously have to question that harm was done,” Savin-Williams says. And again, this kind of play is extremely common. In one study, researchers at Bryn Mawr College found that nearly one-third of women claimed to having been coerced into playing sexual games as children, and that most of the time, these games seemed perfectly normal. Ultimately, the American Academy of Pediatrics says that more than half of children will engage in some type of sexual behavior before their 13th birthday. (For more examples of “weird sexual shit” women did as kids, check out this Tumblr.)

This is not to say that abuse between siblings doesn’t happen; it certainly does. But in no way does what Dunham describe come close to the criminal-justice definition of sibling sexual abuse, which is “forcible rape, forcible sodomy, sexual assault with an object, and forcible fondling.” When child abuse specialists, teachers, lawyers, and child care and school administrators convened at a symposium in 1995 to collectively decide what distinguishes “developmentally expected” sexual behaviors from those that “suggest dysfunctional development” and could be harmful, they decided that masturbation, inspecting the bodies of other children, and kissing—the three things Dunham writes about doing—all belonged in the first category. Behaviors in the second category included oral/genital contact with other kids, penetrating girls’ vaginas with objects or fingers, and forced penetration of other orifices. What Dunham did doesn’t even come close to this.

The fact is, sexuality is a normal and important part of child development, much like the development of language, motor skills, and cognition. It’s only natural that children want to explore their own bodies and those of their parents, siblings, and friends. My son has his hands down his pants more than I would like, sure, but that doesn’t mean he has problems. It means he’s 3 years old. But even though sexual play and exploration is normal, it can be smart to talk to your kids about sexuality at a young age; here are some suggestions for how to do so from the National Child Traumatic Stress Network, and here are some guidelines for how to differentiate normal from abnormal behavior.

Perhaps Dunham was courting a reaction when she wrote, “Basically, anything a sexual predator might do to woo a small suburban girl I was trying.” But that’s just Dunham being Dunham—provocative, perhaps; an admission of sexual abuse, no way. As ridiculous as Williamson’s claims are, they are important to address for two reasons: Williamson is not just being unfair to Dunham by characterizing her actions as “abusive”—he’s also accusing and humiliating millions of other individuals who did similar things as kids. “Our prisons would be filled with ‘child abusers,’ I’m sure, if we started imprisoning all the children who sexually played around with each other,” Savin-Williams says. Perhaps more importantly, Williamson’s accusations trivialize the trauma of real sexual abuse, which, according to the Crimes Against Children Research Center, afflicts an estimated 1 in 5 girls and 1 in 20 boys in the United States today.