(CNN) -- They stare wide-eyed from the pages of magazines, childlike in stature but engaged in extremely explicit sexual activities.
They may be drawings, but critics say the images found on the pages of some of Japan's erotic manga are so disturbing they should be banned.
"I believe that this kind of terrible material is not protected under freedom of expression," says Masatada Tsuchiya, a member of the ruling Liberal Democratic Party.
On Wednesday, Japanese lawmakers passed a law that will see people caught with child porn jailed for a year or fined up to $10,000.
However, it doesn't include possession of anime or manga depicting child abuse, no matter how sexually explicit.
How explicit are they?
To see what's being openly sold on Japanese shelves, CNN took a hidden camera to one of the many manga stores in the Akihabara district of Tokyo.
The district is a known hub for "otakus," obsessive members of anime and manga fandom, a worldwide group of avid followers of the genre.
Down a set of stairs, there are rows and rows of manga, many containing popular themes and images. But five feet away, in an area marked "adults only," the content took a sharp turn into shocking sex scenes, apparently involving minors.
Some of the predominantly female characters wore school uniforms, hair clips and innocent expressions as they engaged in sometimes violent sex acts with dominant characters.
Should it be banned?
Mio Bryce, an expert on anime and manga from Macquarie University in Sydney, said Japan's obsession with "kawaii" or cuteness made it difficult to distinguish whether the characters in the material were depicting children or not.
"Cuteness means a generally more infantile character. Maybe the character is 20 years old, but maybe from your point of view, the character's 15 years old. It's very difficult," she said.
Ken Akamatsu, who lobbies lawmakers on behalf of the Japan Cartoonists Association, said a total ban on explicit content would damage the entire industry, making creators too scared to put pen to paper in case they risked breaking the rules.
He said the characters were imaginary, so unlike real child porn, no one was hurt.
"Actual children suffering and crying is not acceptable. But manga doesn't involve actual children. So there are no actual victims," he said.
Child welfare advocates disagree.
Shihoko Fujiwara runs Lighthouse, a nonprofit for exploited children. She told CNN she once worked on a case where a predator used a cartoon to convince a child that sex abuse was normal. "So the pedophiles might bring the animation and say 'this is how you practice with adults,'" she said.
Child abuse in Japan
While no link has been made between anime, manga and child abuse, Japan is facing a "serious" child abuse problem, according to a White Paper issued by e National Police Agency in March.
The paper said the number of child abuse victims jumped 20% between 2011 and 2012, and the number of victims, arrests and cases are at their highest levels since they started compiling statistics in 1999.
At the same time, the number of cleared child pornography crime cases rose to 1,596, the highest ever recorded, the paper said. Most -- 85% -- were Internet-related. The figures inspired the U.S. State Department to label Japan as an "international hub" for producing and trafficking child pornography.
The U.S. report noted that no national law addresses the "unfettered availability of sexual explicit cartoons, comics and video games, some of which depicted scenes of violent sexual abuse and the rape of children."
It added: 'While the NPA continued to maintain that no link was established between these animated images and child victimization, other experts suggested children are harmed by a culture that appears to accept child sexual abuse."
What is manga?
The term manga means "casual drawing." The earliest examples date back to the 7th century, but it became very popular in the post-war period, Macquarie's Bryce said.
That coincided that with the work of the so-called "God of manga" Tezuka Osamu, the creator of "Astro Boy," one of the more popular Japanese characters that made the leap into Western media.
Now the industry is worth an estimated $3.6 billion in comic book and magazine sales, according to the Publishing Science Institute figures from 2013. Animation takes in another extra $2.3 billion, according to the Media Development Research Institute.
As Bryce points out, only a very small proportion of the market peddles sexually explicit material involving children.
"Very often people think manga equals sexual or manga equals violence. But it's only a part of manga... there are some very poetic, very beautiful ones," she said.
'Cuteness is a problem'
The bigger problem, she said, is that manga permeates Japanese culture. It can be seen everywhere, from street signs to government pamphlets.
Often, the characters depicted are young, vulnerable girls who meet consumers' desires for something "kawaii" or "cute."
"'Cuteness is a problem," she said. "Because cuteness is something that makes you feel you have to protect the person, and there's a very fine line between 'I can protect the person' and 'I can control the person.'"
She said the prevalent depiction of young girls, especially in "Lolita complex" material, risks giving "the wrong impression of women."
"If you're looking at it all the time, how are you actually seeing people? Is it just a fantasy, or maybe some people with a bit of a wrong mind think that is actually there, and that is the way to treat women. So there is a risk," she said.
CNN's Yoko Wakatsuki contributed to this report.