By age 24; Lu pansheng could be considered a man of the world. He had raised rubber trees on far-off Hainan Island, dodged police in the big city of Canton for months, and swum across sharkfilled waters to Hong Kong.

Yet, that same, wiry, long-haired 24-year-old said he had never attempted, and could not even describe, the sex act.

To Americans, Lu's sexual innocence borders on the absurd. But many Chinese told this story say they are not suprised. For millions of other young adults in China, despite their country's role as the world's leading baby producer, sex, has become an annoyance and a trap, something better left unexplored and not even though about.

"Most youths in China are concerned with their futures, so they spend their spare time studying to get to a university, or to get an urban job, or to find a way to emigrate," Lu said. Many city-raised youths sent to work on farms in the countryside "keep themselves away from love because they believe that if they have an affair, and a baby, it requires marriage and means they would have too little chance of leaving the farms."

In the countryside, where 80 percent of the nearly 1 billion Chinese live, men and women lead very separate lives.

Even in this supposedly revolutionary society, pairing off, is looked on with suspicion. Urban youths accustomed to girl-boy joshing at coeducational high schools and colleges have been stunned by the change of attitudes when they move to the countryside. Many have quickly adopted the sexual divisions practiced by their country hosts, to the point of not talking to old classmates of the opposite sex, even when passing each other on a tree-shaded rural goat path.

No one has calculated how many young Chinese men and women go to their marriage beds not really knowing what they are supposed to do. The Chinese say misinformation is rife. In some southern rural villages, girls reaching puberty are sent to chat with women who are older and "experienced" -- meaning those with lots of children. The sessions often are obscured by the prevading peasant reluctance to delve deeply into the subject of sex.

In a delicate way, the Communist Party has attempted to shine a little light into this dark rural corner. One health worker reported "the commune delivered a small book to married couples at their wedding ceremonies. It described how to raise their baby, all aspects of married life, also birth control, but it had no pictures . . . It began with a quote from Chairman Mao on the significance of birth control, then discussed particular, contraceptive methods and devices."

Despite cultural restrictions, even in China there are some unmarried lovers who seek to tempt fate. "Some people would wait and try to meet at night," said one young Chinese from Hunan, "others would find an excuse to take off from work in the fields during the day, and perhaps meet among some trees, or go back to the dormitory if there was no one there."

But for the vast majority, romance and finding a mate are circumscribed sharply both by custom and by living conditions.

In the tightly packed life of a Chinese village or housing development, young people cannot avoid rubbing elbows. Proximity and familiarity sometimes weaken romantic urges, an experience not unfamiliar to American college students in coeducational dorms.

Chinese parents often prefer to look outside their own village for suitable mates for their children, since this extends the family's contacts and acts as a hedge against economic disaster. "If the crop fails, we can move in with Huailing's inlaws," one peasant said.

That is the way people have preferred to do it for centuries, but the old custom violates the modern notion that young people should pick their own mates.

The gradual economic modernization of the countryside sometimes helps bring a compromise. Some young men say they volunteer willingly to work on massive dam or road projects, which take people from several villages since it gives them an opportunity to meet new girls.

If a youngster passes the exam for the commune's senior middle school, he or she will meet other bright youth of the opposite sex from outside the home village. Jobs in a seasonal factory, making toothbrushes or tractor parts, lure eligible young men and women living several miles from each ther.

Courtship remains a problem. Privacy does not exist in China, except for, the most resourceful or fortunate citizens, for there just is not enough space.

Many Chinese welcomed in a way the great north China earthquakes of 1976, and the damage and danger of aftershocks that forced the construction of mud-brick shelters with bamboo mat roofs in the front yards of apartment buildings. Some couples saw their first chance for a night alone in years. They sent children and grandparents to the shelters, gladly accepting the risk of a night by themselves in the crack-walled apartment buildings.

In a nation without private automobiles, basement rumpus rooms or drive-in theaters, it is difficult to find a place to do much more than talk about romance. The only reliable way a young couple can find a measure of privacy in China is to take a long walk. At dusk, on the streets of every Chinese city I have visited -- Canton, Peking, Shanghai,Kunming, Wuhan, Chongping, Nanning Gullin and even a little peasant village like Dazhai. I have seen numbers of young men and women out walking.

They wear faded blue coats and slacks, neither male nor female betraying any effort to dress up for the occasion. Sometimes they hold hands, although urban youth are bolder at this than their country cousins.

One night, in a dark, dung-strewn Canton alley, I tripped over a couple clothed. There were others in the alley, and I retreated. It was a chilly evening, and there really was no other place they could go.

In Shanghai, on streamy spring nights, couples carve out a little space on the broad, crowded walkways of the Bund -- the riverfront -- by deft use of umbrellas. An American diplomat, fascinated by this practice, developed what he calls "the umbrella theory of Chinese love." As the umberllas draw closer together, so does the relationship. If a couple appears with a single umbrella and huddles behind it, their engagement is imminent.

On a bulletin board near Shanghai's People's Park, a former race track now suitable for romantic trysts, a printed sign gently counseled moderation. Love is a normal thing, it said, but young men and women should treat it with pure motives. People should not really talk about love during working hours. Too frequent dating might distract them from their work for the state. h

The sign added a recommendation of late marriage, perhaps 28 years old for men and 25 for woman, and advised building a happy home life with no more than two children.

One night in Canton, I joined the most excited movie crowd I had ever seen in China. A 1957 romantic comedy, long banned by the extremist "Gang of Four," had just been rereleased. Its plot was as familiar to Chinese audiences as "Snow White" is to Americans.

A young peasant girl's father, down on his luck, arranged to clear his debts by marrying her to the vilage's weathiest lecher. The girl herself pined for a handsome young vegetable grower. This boy was so timid and engrossed in his cabbage production that he hardly seemed worth the effort. But he was dazzlingly good-looking.

The love scenes, if that is what they can be called, embodied the aching shyness of peasant youth. The young couple exchanged dumb and anguishing looks from afar. An older aunt urged the girl on. The boy's workmates encouraged him -- like nearly everything else in China, love was a group activity.

The star-crossed lovers, despite their beating hearts, seemed unable to conquer a quivering fear of actually speaking to each other.

As simplistic as it was, the film electrifled the young people who had jammered into the cramped and stifling balcony of the downtown theater. The audience giggled, whispered, and sat forward on their seats. The story on the screen seemed to sum up all their own fears of contact with the opposite sex.

After several years in a narrow, proletarian straightjacket, fiction works coming off Chinese government printing presses also are now dipping into such delicate matters as love and romance. Even with some new literacy freedoms, however, love stories carry a sense of distance, of affection from afar.

The central themes are still work and sacrifice, the need to pass an exam, plow a field, repair a truck, or catch a fish for the good of the people and the state. Love is a sideline, a workshop bonus like the $3 to $5 prizes passed out to whoever can turn out a record number of bicycle gears.

While the screen and written versions are tame, real-life romantic scandals have fueled gossip in Chinese villages, particularly during the social dislocations and political lawlessness of the late 1960s and 1970s.

Young female junior high school graduates were sent to the countryside during that period without sufficicient food or farm work experience. They were painfully homesick and provided convenient targets for unscrupulous rural officials.

As the campaign to send such young people to the countryside began to disintegrate in the mid-1970s, stories surfaced in unofficial wallposters and even in the official press about officials who gave extra food easy jobs or permission to travel in return for sexual favors.

"We are sure one or two women students in our brigade did something like that to get good factory job assignments, and get away from work," said one Guangdong student.

Rapid political changes and liberalization, like those beginning in 1978, have stimulated a few sexual experiments in Chinese cities, and corresponding gasps of horror from the press. A Shanghai radio broadcast in early 1979 complained that "in the streets, some people openly sell indecent photographs and some young men who have dyed their hair blond and set it in permanent waves are flirting and walking in an effiminate manner . . . .Some photo studios display pictures of bare-breasted women to attract customers."

One young man named Zhang Yide, the broadcast said, sold "4,700 extremely obscene" pictures in a couple of months before he was caught.

But that is city life, and if there is any sign that China's ancient peasant reticence, almost callousness, about sex has softened significantly lately, it is not readily apparent.

The system has even occasionally affected foreigners. Andre and Lyn Kirkpatrick, a married student couple from Britian, were forbidden to live together when they arrived in Shanghai in late 1976 to study. They slept in separate, crowded dormitories, and were forced to lead celibate lives, just as their unmarried fellow students did. When a European businessman allowed them to spend the night together a few times in his Shanghai home, he was reprimanded by the local public security office.

"There is the concern about the future, and a firm commitment to the traditional conservative Chinese view toward sex," said Lu Pansheng, the young man who himself avoided examining the subject until he left China for Hong Kong at age 24. "Young people are just very reluctant even to talk about such matters."

When two Chinese students at a Shanghai university were caught making love in the bushes, the man was imprisoned and the woman committed suicide. Classmates publicity criticized the pair because "they let themselves go while others have to hold themselves in."

One official directive, summing up the problem, advised young men that wandering sensual thoughts might best be handled with a cold bath.