What was going on when I was born?

International A British destroyer was disabled and set afire by an Argentine jet fighter, Britain announced. The destroyer Sheffield, struck by a high-explosive missile, was abandoned and was said to have sunk. Defense Minister John Nott said that as many as 30 members of the crew, which normally totals 299, might have died despite intensive rescue efforts. In Washington, intelligence sources said that a major naval battle was still raging off the Falklands. Earlier, Britain announced that a fighter-bomber had been shot down during a raid on air strips in the islands and that the pilot had been killed. (Page A1, Column 6.) Argentina announced the rescue of at least 680 survivors from the torpedoed cruiser General Belgrano and said that a search was continuing for the 362 other crew members. The American Embassy in Buenos Aires said it was evacuating ''nonessential personnel'' and dependents. (A1:5.)

CUISINE By MOIRA HODGSON UNTIL recently, cooks in the United States looked to Europe for inspiration. But now there is a serious attempt being made to define and practice a new American cuisine. It is an inventive and eclectic style adopted by a growing number of young chefs across the country. Their ideas may borrow from the French nouvelle cuisine but the dishes are totally distinctive because they are made from American ingredients - quail raised in New Jersey, scallops from Nantucket, wild mushrooms gathered in the mountains of Oregon. This style has actually been evolving for a number of years, ever since the cooking boom first hit this country in the early 70's, bringing with it a proliferation of fine restaurants, specialty shops, cooking classes and best-selling cookbooks. But it has come into its own more recently as food producers, many of them small cottage industries, have developed sources in this country for items that have either been long neglected or once came only from Europe. These include fine milk-fed veal, Charolais beef, goat and blue cheeses, Brie, morels, chanterelles, olive oil and sweet, succulent oysters from Hawaii that are now being exported to France. Many of these products are raised in remote parts of the country and then flown in, while others are raised locally on small farms that supply restaurants and even some retail stores, making them available to home cooks, too.

The Economic Scene column in Business Day last Friday incorrectly indentified Charles L. Schultze. He served as Director of the Budget in the Johnson Administration and as man of the Council of Economic Advisers in the Carter Administration.

Mother's chicken soup, move over. Father's chicken soup, specifically, divorced father's chicken soup, is advancing from the back burner. The recipe appears in the current issue of Divorced Father, a new monthly newsletter. ''Your kids can take it home in a jar,'' the publisher suggests. ''They'll think of you all week while eating chicken soup.'' Mixing it up in the kitchen is becoming a popular pastime for divorced fathers who do not have custody of their children. Rather than play the cliched roles of Zoo Daddy or McDonald's Daddy, growing numbers of weekend fathers are turning to cooking as a less expensive, more natural way of being together. ''Noncustodial cooking,'' they call it.

Britain's allies reacted with shock and dismay today to the sinking of the Argentine cruiser General Belgrano, with the presumed loss of many lives. News of Argentina's retaliatory attack against the British destroyer Sheffield reached Europe too late at night for reaction. But even before the news of the British loss, European governments were calling for an end to the fighting, in the interests of both sides. In Washington, Secretary of State Alexander M. Haig Jr. abruptly canceled a trip to New York for a speech and rushed back from the airport to the State Department, where he met for three and a half hours with Sir Nicholas Henderson, the British Ambassador. (Page A16.)

The nation's synthetic fuels industry, started with great fanfare and billions of Federal dollars less than two years ago, today stands demoralized and uncertain. Its future is jeopardized by falling oil prices, high interest rates, soaring construction costs and an Administration determined to leave energy development almost entirely to the free market. The latest blow came when the Exxon Corporation and the Tosco Corporation announced an end to their Colony Oil Shale Project in western Colorado, the centerpiece of a synthetic fuels industry that has been plagued with problems from the beginning, and whose ambitions had already been drastically scaled back. 'It's a Setback' ''It's a setback not just for the synthetic fuels industry but for our whole international economic and political strategy,'' commented Robert I. Hanfling, a Washington consultant and former synthetic fuels specialist at the Department of Energy. ''Synfuels just fell by the wayside.''

An Argentine jet fighter set afire and disabled the British destroyer Sheffield in the South Atlantic on Tuesday and the ship was abandoned, the Ministry of Defense announced. The Sheffield, struck by a high-explosive missile, was reliably reported early this morning to have sunk, but a ministry spokesman said he had no confirmation. Defense Minister John Nott said that as many as 30 members of the crew, which normally numbers 299, might be dead, even though ships near the Sheffield had plucked many survivors from the icy winter seas. Most of Crew Is Accounted For ''Nearly all the ship's company and captain are accounted for,'' Mr. Nott told the House of Commons in a statement demanded by irate members. ''The task force is continuing with its operations as planned.''

A report in the Briefing column on the Washington Talk page yesterday incorrectly stated the political party of Representative Richard L. Ottinger of Westchester. He is a Democrat.

President Reagan agreed today to impose quotas on sugar imports as a means of saving the Federal Government several hundred million dollars under the price support program for domestically grown sugar that he accepted last year in return for farm-state Democratic votes for his budget. The quota decision was reached during a Cabinet council meeting this morning at the White House, industry and Congressional sources said. It would eventually force domestic sugar prices for major industrial users up about 4 cents a pound, to about 20 cents a pound. These price increases, in turn, would be passed on to consumers, probably at even higher levels.

No guns have been brandished nor shots fired, but a ''bloodless war,'' as one Government official put it, is raging in Japan. At odds in the battle are the nation's two most powerful political constituencies: the business community and the agricultural lobby. It is big business, especially representatives of export-dependent manufacturing industries, versus small farmers - the most efficient sector of the Japanese economy against the least efficient. The conflict shows that while Japan may be more tightly knit than most Western nations, it by no means speaks with one voice. Nor is its Government immune to the claims of special-interest groups or the realities of partisan politics.

MILK is indisputedly the ideal food for infants and an excellent food for young children. But as people get older most lose their ability to digest it fully. This happens because intestinal production of the enzyme lactase declines with age in all but a small segment of the world's population. Lactase is needed to split the two-part milk sugar lactose into its component sugars, glucose and galactose, so that they can be absorbed through the intestinal wall. Adult lactase deficiency is so common that it is considered the normal state of human affairs. Only in northern Europeans and their descendants and in two African tribes do most adults retain their childhood ability to digest lactose. An estimated 30 million Americans cannot digest lactose properly, and among certain ethnic groups - blacks, Asians, Mediterraneans, Jews, southern and central Europeans and American Indians - 70 percent or more have difficulty digesting lactose as adults. The Problem. When someone with a lactase deficiency consumes large amounts of a lactose-containing food at one time, much of the sugar passes undigested through the stomach and into the intestines, where it absorbs a lot of water and becomes food for intestinal bacteria that form gases and acids. This often results in such symptoms as abdominal bloating, flatulence, cramps, loose stools and watery diarrhea.

President Reagan agreed to impose quotas on sugar imports. His aim is to avoid having to buy and store domestic sugar under the price support plan he accepted last year in return for votes for his economic program. One result will be to raise the price candy companies and soft drink producers pay for sweeteners. (Page A1.) New-car sales by the Big Three auto makers fell 5.1 percent in late April, the companies reported. G.M.'s sales rose 1.7 percent, but Chrysler's dropped 34.1 percent and Ford's 4.4 percent. Analysts attributed the decline to a lackluster response to incentives as well as poor economic conditions and high interest rates. (D1.)