While screening minors from explicit sexual content is to be welcomed, sexting between consenting adults is a different matter and privacy laws should protect people's rights.

China and the United States are simultaneously cracking down on sexting -sending sexually related messages or photos via mobile phone.

There are differences, though. In China, it is part of a broader campaign to eradicate sexual content from all digital distribution channels. In the US, the focus is on teenagers who send photos of their private parts and end up being harassed.

Suffice it to say, if a teenager in China did that and fell victim, there would be little sympathy for him or her. Witness the Edison Chen incident. Even though the Hong Kong star is an adult and his notebook was hacked, which resulted in the dissemination of his sexually explicit photos, his career has been put on infinite hold.

Cultural and ethical mores differ from country to country.

Unlike the US, China did not have a pornography industry before the age of the Internet - at least not since 1949. Lurid photos and videos came as a big shock. Depending on which side you take in the sexual liberation debate, this is either the best or the worst fallout from a technological revolution. It is definitely going to reshape moral values down the road.

Sexting started in China earlier than in the US because text messaging was adopted as a mainstream mode of communication first on these shores. There have been periodic efforts to target it as a harmful medium. The new campaign is marked by simplicity: If you send out a sex message, your service will be suspended.

Simple, or too simplistic?

First, how to define sexting? I'm sure there are words equivalent to those on American broadcast networks that are bleeped. But most of these words have multiple meanings in a Chinese context. Take the Chinese equivalent of the f-word. In most circumstances, the all-inclusive word for "do" is used rather than a specific word for the activity.

Which takes me to my second point: How to detect sexting? The logical method is to set sensitive words. But, some of these words are only "sensitive" in a special context. Besides, we have developed, over time, various ways of circumventing sensitive words by adopting homonyms. The latest generation of netizens has elevated this to a new level of sophistication.

The only safe way to accurately screen sexting is for real people to do the job. But you know how many text messages people send out in one day? China Mobile, alone, reported late last year that it processed 1.5 billion messages on a daily basis. So, it'll take an army of millions to do the job adequately. On the plus side, I now know where our 6.1 million college graduates can find work, thereby turning a high-tech industry into a labor-intensive one.

Of course, I'm kidding. But pornography is a serious matter. It'll corrupt our youth, leading them from rote learning into dens of iniquity.

But shouldn't there be a line between sex content for private consumption and that for mass distribution?

In the past decade, there were two cases, both overturned, that illustrated the progress of our legal protection of private rights. One involved a couple who were busted while watching a sex video in their own home. Another was a man whose cellphone was taken by a policeman and found to contain an explicit video clip. In both cases, the accused were first charged or fined, then exonerated.

If a husband texts his wife, using erotic words, to let her know that he misses her - think Prince Charles and Camilla Parker-Bowles - does that warrant the penalty of service suspension? What if the recipients are good friends who share dirty jokes face-to-face? Do they have the right to continue the practice on mobile platforms?

In my understanding, what the law forbids is sexting as a broadcast tool - either for profit or harassment. We should shield minors from such exposure. But outlawing something like a bawdy joke - especially one told in private - is not really feasible, and possibly threatens privacy and other rights. The totally politically correct CCTV Spring Festival Gala is sprinkled with these kinds of jokes, but because they are coded and understood only by adults they pose no harm to the young. Likewise, a joke tastefully told - within the context of Chinese ethics - should not be cause for alarm.

Here, I may stand accused of blurring the distinction between graphic depiction of sex with the more innocuous erotic humor. I feel I know where to draw the line. Most people have an instinct about what is appropriate to send to which friend. For a mobile carrier or its regulator to ban certain rights of speech, shouldn't they at least first specify what is forbidden to text?

In his perpetual rebelliousness, writer Han Han said he was going to test the system by sexting to both male and female friends and see which texts were blocked. He wrote: "I've never seen anyone enraged by a sex message. There are only two reasons why one may be annoyed by such a message: One, it's not funny; two, it's one you just read and forwarded to your friend."

But he suspects - sarcastically - there will be a survey showing "90 percent support" for the crackdown because sexting has distracted students from concentrating on their exams for post-graduate study or their civil servant applications.

The hilarious cellphone ad for a hard-core sex service, which Han describes, is the kind of thing the government possibly intends to wipe out but slips through the cracks because it does not contain any bad words.

A really interesting experiment I can devise would be the composition of text messages that use propaganda terms yet would totally violate our moral codes when placed in a special context. Someone I knew from grad school used to trot out political slogans and - with a wink - turn them into smut. I wonder what the telecom censors can do about them.

Every generation of youngsters is a target of protection from unhealthy content. In the 1980s, Michael Jackson was not allowed to perform in China partly because he loved to "grope himself" on stage. In the 1950s, Elvis Presley gyrated to screaming teenagers and to the discomfort of their parents. Someone whisked by a time machine from two generations ago might frown upon even the most puritanical form of dating and mating extant today.

While people have a right not to be harassed by sexting, they also have the right to their privacy, which should not be sacrificed by a moral crusade. So, why throw out the "baby" of growing awareness of personal rights with the "bath water" of cellular smut?