The U.S.S.R.

All looked uncommonly like a soap opera. In a sleepy Siberian town where people are slogging through 10 feet of snow for much of the year, Valery became enchanted by Olya. She loved him and became pregnant. He, however, found his true love in a certain Lera.

Now, the miserable Valery was torn between his obligation toward the baby and his affection for Lera. He married Olya--the honorable thing to do--but he vowed to remain faithful to Lera.

You can almost guess the rest. Olya was unhappy because Valery avoided her. He came home late and occasionaly beat her. Lera was miserable because she loved Valery and could not have him. Friends and relatives were taking sides.

The unexpected in this drama is that the main characters are all about 14, that they are eighth-graders, that theirs is far from being an isolated case of teen-age pregnancy, and that they are the focus of a gingerly conducted public debate about one of the taboo subjects in Soviet life--sex.

THERE WERE TIMES immediately after the Bolshevik revolution when Russia was regarded by the world as a land of sexual promiscuity. In those years the Bolsheviks set out to eradicate what they called the "bourgeois mystification" of sex. One of Lenin's collaborators, Alexandra Kollontai, advanced the so-called "glass of water" theory of sexuality: that sex satisfies one set of physiological needs much in the way drinking a glass of water satisfied another.

Since then, however, the Soviet Union has reverted to its peasant traditions to become a bastion of Victorian virtues. In contrast to Americans, Soviets frown upon public expressions of sexuality and are visibly uncomfortable when the subject comes up in private conversations.

Current literature, film and television ignore the subject. They relegate women to the role of supportive mother, brave sister who carries important information through enemy lines or young maiden building socialism. Open eroticism is officially prohibited as a symptom of bourgeois decadence.

Indeed, the sad tale of the three Siberian teen-agers might have stayed unknown if this country were not facing difficult demographic problems such as a decline in birth rate and increase in infant mortality. While these indicators are linked to the country's urbanization and deteriorating health services, they are also a reflection of what is termed here as "appalling ignorance" about sex. Olya, for example, was seven months pregnant before realizing "something was wrong."

The Siberian tale came to light when Lera wrote to the newspaper Komsomolskaya Pravda describing her predicament and asking, "What should I do? Help me resolve this thing."

The newspaper sent a reporter to investigate. The resulting story talked about "irritable teachers" who were only concerned about "shame for the school" and could not think of anything but disciplinary action to deal with infractions.

The poor Olya has turned into "a little, incomplete and angry woman." Her parents have forced her to move in with Valery's parents for the sake of appearances, only to stop "ugly" rumors. Lera turned out to be vindictive and confused and Valery morose and uncommunicative.

BUT THE MAIN message conveyed to the reader is that there are too many educators who contend that "our children should remain innocent" until they reach 18.

The position was criticized by the vice president of the Academy of Pedagogical Sciences, Antonina Hripkova, who proposed that sex education be introduced in Soviet schools. She said "intimate questions" of sex should be taught separately to boys and girls but they should be taught.

In writing about the situation of Valery, Olya and Lera and advancing the solution, Komsomolskaya Pravda said that both parents and teachers are opposed to the introduction of sex education. It told how in another school in another city a young girl had a child and a doctor was sent to tell the children something about the facts of life, but "they did not let him in the door."

Responses to the newspaper article and Hripkova's proposal were mixed. Workers of an automobile plant, for example, got together to formulate their "complete opposition" to any sex education course "that would include discussions about pregnancy."

A woman from Estonia said in her letter: "Not Olya but you, the grown-ups, should be ashamed for ignoring important questions in schools."