My son is 16 years old now," a middle-aged Cuban remarked over breakfast at a quick-service counter. "That means he has to sign up for military service this year."

"Of course, as a parent," he said, "I am frightened" of the possibility that the boy may be sent to join the estimated 40,000 Cuban combat soldiers now in Africa.

But as a Cuban, he is proud. "These families who don't have anyone to go," the father said, "are ashamed."

While Americans may compare Cuba's participation in faraway wars on another continent to the U.S. involvement in Vietnam, many Cubans clearly view it in an altogether different light.

For Cubans such as this father - and most probably his son - the cause in Angola and Ethiopia is seen in the same way that Americans saw their role in World War II.

The Cubans think of themselves as making a valiant national sacrifice in the name of human liberty. It is good guys versus bad guys.

During nearly two weeks of discussions with dozens of Cubans of different ages and occupations, I found those willing to voice opposition to their government's policy in Africa few and far between.

Those few included parents whose fear for their sons outweighed their patriotism, those who felt the money spent overseas was vitally needed at home and those who dislike everything about the Cuban revolution.

Doubtless, there are those who do not speak up for fear of being labeled "counterrevolutionaries" in a society where one of the biggest sins is disagreement with established policy.

But the vast majority of those dozens, an admittedly small sample of Cuba's 9.6 million people, were outspokenly in favor of sending Cubans to fight, and perhaps to die, in lands that two or three years ago they had never heard of.

To understand why is to understand what has been a fact of life in Cuba for nearly 20 years. Since Fidel Castro first led his victorious guerrilla band into Havana, Cuba has been a nation mobilized for war. Only during the 1961 Bay of Pigs invasion, however was there anyone to fight.

While what Cuba feels is economic "aggression" continues, through the crippling U.S. trade embargo, it has grown increasingly difficult to whip up the kind of fervent militarism that initially sustained the Cuban revolution.

In an interview, Vice President Carlos Rafael Rodriguez said that Cuban youth, the bulwark of the country's militant solidarity, was missing a "mobilization ingredient." Military service, in which young Cubans once took pride, had become something with which parents threatened unruly children, a place where the government stashed "anti-social elements."

"But the tasks of international cooperation" in Africa, Rodriguez said, "help the revolution."

Since troops were first sent to Angola in late 1975, Cuba has maintained that all Africa service is voluntary, and that reservist, rather than active-duty soldiers, are chosen.

In many ways, every Cuban is a military reservist. Although youngsters must register for military duty at 16, the standting army does not have nearly enough spaces for all of them. Some, with high aptitude test scores, go directly to universities, others into vocational schools or non-skilled occupations. Some are selected to attend military academies, from which they emerge as active or reserve officers.

Reservists, who can range from 18 to 50 years of age, apparently are called up for Africa duty by geographic units. While some Cubans said refusal to go to Africa meant loss of jobs or other more serious punishment, even imprisonment, others said anyone "with a good excuse" could decline.

"You say you have a sick mother, or a lot of kids," said a Havana bricklayer. But for many, he said, service in Africa is a mark of prestige, a way of breaking out of the vestiges of social and economic classes that still exist in post-revolutionary Cuba.

While the United States might have trouble finding jobs for Vietnam veterans, every Cuban who serves overseas is reportedly guaranteed the same or a better job on return from a one-year tour of duty in Africa.

More importantly, said the bricklayer, each veteran "comes back with a certificate saying he's an internationalist fighter. It means you're a national hero and, if you want, you can call your boss a son of a bitch" and get away with it.

"I'm too old to go," he said, "and I don't want to go. But I can understand why young men want it. It's a way of getting out to see the world, just like in any other country."

U.S. and Cuban officials agree that Cuban casualties in Africa have been relatively slight. Those who are killed are buried on African soil. Cuban officials said that the families of falledn soldiers are given an income.

With outside information limited to Miami radio programs and Soviet magazines, virtually all of what the average Cuban knows about his country's involvement in Africa comes from the government's speeches and newspapers, or from propaganda distributed and discussed within the Committees for the Defense of the Revolution. These neighborhood groups throughout the country previde ideological training and an organizational infrastructure for government programs.

Felipe Suarez is the Committees' national director of African and Middle East affairs. In addition to organizing local "solidarity activities" in sympathy with socialist nations in Africa, Suarez said the committees disseminate propaganda material designed to explain to the masses what their sons are doing overseas.

In the case of Ethiopia, where according to U.S. estimates 15,000 Cuban troops are stationed, the propaganda concentrates not on the current struggle against invasion from Somalia or secessionist battles in Eritrea, but on a liberation struggle from a feudal empire that fell more than three years ago.

"A constant topic" in discussion groups, Suarez said in an interview, "is the fight against exploitation. We explain Ethiopia in terms of how those people lived under Haile Selassie, and how 60 families owned everything while many died from drought and malnutrition."

Those who study the material appear to agree. "In the internationalist fight," said a member of a 38-member committee an hour's drive from Havana, "we have a clear concept about Cuba's aid. We have discussed Cuba's internationalist duties."

Three sons of this village have gone to Africa, and one has returned. "If the country needed him," explained the sugar can farmer whose son came back, "then it was his duty to go. He had some fear, but he was selected, and he went to help a brother country. He wanted to go."