What was going on when I was born?

Guerrilla forces have dealt a blow to the Government by capturing the southeastern Salvadoran city of Berlin, demonstrating that they can ''roam at will and raise havoc,'' according to a military source close to the situation. With their victory, won on Monday, guerrilla forces now control one-third of the rich agricultural province of Usulutan. The source said it was questionable whether the guerrillas could hold Berlin, the province's second largest city. But he said they appeared to be in a position to do considerable damage to the economy and even mount an attack on the provincial capital, also known as Usulutan, which is 20 miles southeast of Berlin.

House Democratic leaders unanimously committed themselves today to an emergency economic assistance program that would create public service jobs, provide shelter and soup kitchens for the destitute and avert foreclosures of homes and farms. In pressing this legislation, the Democrats plan to dramatize the plight of the worst victims of the economy and depict on the House floor the struggles of the homeless, hungry and dispossessed. By moving along such a broad front, the Democrats hope to seize the initiative from President Reagan and provide a contrast with his insistence on additional cutbacks in social programs. ''With 14 million people out of work, the highest number in history, it is time for a combined program of relief, recovery and reconstruction,'' Speaker Thomas P. O'Neill Jr. said after a two-anda-half-hour meeting with all 25 House committee chairmen.

The Agriculture Department announced today that it was scrapping a five-year-old program to create wilderness areas in national forests. Instead, the department said it would re-evaluate areas already recommended for protection in the wilderness system. The decision again throws wide open the issue of how much of the forest system will be protected as wilderness and how much will be open to timber interests and other developers. Assistant Agriculture Secretary John B. Crowell Jr. said the reevaluation would be done on a forest-by-forest basis and could take up to two years at a cost of up to $30 million. In the meantime, he said, timbering and other development will be permitted in forest areas without roads that were not previously recommended as wilderness areas.

Yuri V. Andropov, the Soviet leader, today dismissed President Reagan's proposal that they jointly ban their medium-range nuclear weapons as ''the same 'zero option' '' that Moscow has already found ''patently unacceptable.'' Mr. Andropov accused Mr. Reagan of treating the question of a summit meeting lightly by making it conditional on Andropov remarks, page A8. the American negotiating proposal. ''This can only be regretted,'' he said. The Soviet leader issued his response to Mr. Reagan's letter in the form of an interview with the newspaper Pravda.

Stanley Fink, the Assembly Speaker, said today that the Legislature might consider raising the state's major taxes to avoid the proposed laying off of more than 8,000 state workers. Increases in the taxes - on personal income, sales and corporate profits -were emphatically rejected by Governor Cuomo in proposing a $31.5 billion state budget. He called the increases counterproductive and said he had made a campaign ''commitment'' not to raise the taxes.

Four Arab members of the Organization of Petroleum Exporting Counties threatened yesterday to reduce their crude oil prices by $4 a barrel within a week unless other OPEC members agreed to adhere to production ceilings. The threat, reported by Kuwait's official news agency, was an indication that the Arab countries along the Persian Gulf might abandon OPEC's official prices. These prices, based on $34 a barrel for Saudi Light crude oil, have been eroded by discounts offered by other members and by steadily weakening prices on the free market. The Nations Involved The news agency said Kuwait would be joined in the price cuts by Saudi Arabia, OPEC's largest producer and the world's largest oil exporter, the United Arab Emirates and Qatar, all neighbors on the Persian Gulf. Two other Gulf nations, Oman and Bahrain, which are not OPEC members, would also join the move, the agency said.

EATING is a perfectly natural activity, we all have natural urges to eat, and we should be able to satisfy those urges simply and naturally without shame and anxiety and numbing self-consciousness, either alone or with one other person or two or (if we prefer, and it's strictly a matter of personal preference) with larger groups. It should be a joyous life-affirming experience, not (as I'm afraid it is for so many) A Problem. When I was a boy, away out on the open prairie of the American heartland, we were happy eaters and weren't ashamed to have big appetites. Out there in Breughel, N.D., surrounded by an ocean of durum wheat, we got three squares a day, piled our plates and cried ''Yes!'' to seconds. Tables groaned at picnics, church suppers, Sunday dinners, holiday feasts. Food was a relief against our flat landscape: steamy mountains of fried chicken and pork among foothills of creamed onions, spinach, mashed potatoes with lakes of gravy and great promontories of pie. At least once a week we sat down to table and scaled the Sierras. And what we called ''a little lunch'' would knock the socks off Pavarotti.

Two vans carrying paintings and furniture valued at more than $400,000 back to their owners from the Winter Antiques Show in Manhattan have been reported stolen. The weeklong show, an annual event at the Seventh Regiment Armory, at 67th Street and Park Avenue, closed Sunday, and individual exhibitors had begun packing up and trucking away their unsold wares on Monday. Sponsors of the show said that such large thefts were unusual and that crime had not been a problem at the show. The vans were taken from two different locations - one in Manhattan, the other in Connecticut - after their drivers left briefly and returned to find no trace of them.

AN ambitious study of 521 Boston families presents new evidence of the prevalence of child sexual abuse and offers the first detailed portrait of parents' knowledge and attitudes about the problem. The research finds that the majority of parents have the misconception that child sexual abuse is committed primarily by strangers and shows that most parents cannot bring themselves to warn their children appropriately about the potential hazards of child abuse. However, the investigators found that parents are surprisingly well informed about the existence of child sexual abuse, believing it to be alarmingly common. The parents interviewed overwhelmingly supported education in their children's schools about such victimization. The two-year, $210,000 study, directed by Dr. David Finkelhor of the Family Violence Research Program at the University of New Hampshire, was financed by the National Center for the Prevention and Control of Rape, a branch of the National Institute of Mental Health. The interviews were conducted by the Center for Survey Research, an organization sponsored jointly by Harvard University, the Massachusetts Institute of Technology and the University of Massachusetts. Among the key findings were these: * Nearly one parent in 10 - 9 percent -said that their own children had been the victims of abuse or attempted abuse. Four of the parents interviewed had had two children abused.

''I now know the answer to what it takes to move a slightly cantankerous, slightly bewildered, aging elephant - a question that I have been asking myself for over a year.

Pedro Fischer, a leading Argentine textile manufacturer, had a simple explanation of how he does long-term business planning in a country that has an inflation rate of more than 200 percent: He doesn't. ''To an Argentine businessman,'' said Mr. Fischer, with black humor that belied his exasperation, ''short term is until tonight, medium term is until the end of the week, and long term is until the next change of economics ministers.'' Interviewed in his bustling women's garment factory in this suburb on the outskirts of Buenos Aires, Mr. Fischer, 62 years old, is in many ways a typical Argentine businessman. He has learned to be extraordinarly adept in his business, devising tactics that an American might find boggling.

Four Arab members of OPEC threatened to cut oil prices by $4 a barrel by next Wednesday unless other members of the group accept production ceilings. The threat seemed to indicate that the four, including Saudi Arabia, are ready to abandon OPEC's official price structure. Meanwhile, nine U.S. companies lowered the price they will pay for domestic crude. (Page A1.) In Western Europe, a decline of a few dollars a barrel would create more winners than losers, economists said. (D1.) The World Bank plans to speed lending to developing countries. A plan to accelerate disbursements, requiring the bank to increase its borrowing, is likely to win U.S. assent. (D13.)