What was going on when I was born?

In a move that would end nearly 20 years of involvement in the Dominican Republic, Gulf and Western Industries said yesterday that it would try to sell its sugar growing operations and holdings there. ''Sugar no longer fits in with the company's long-term strategic plan to concentrate principally on higher return, consumer-oriented products, financial services and leisure time businesses,'' said Martin S. Davis, chairman and chief executive officer. The company, which a year ago announced write-offs of $470 million to divest itself of several major lines of business, will also end its sugar activities in Florida. Gulf and Western said that the write-down from the sugar operations will reduce third- quarter income by about $30 million.

A report in New York Day by Day yesterday about Bella Abzug's possible candidacy for the House of Representatives in Westchester County incorrectly described the residency requirement. House members need only to be residents of the states that elect them.

The Senate tonight approved a compromise measure that would forbid Pentagon spending to test American antisatellite weapons unless President Reagan certifies that he is ''endeavoring, in good faith to negotiate the strictest possible limitations on antisatellite weapons.'' The 61-to-28 vote came as the Senate continued debate on a $213.5 billion military authorization bill for the 1985 fiscal year that begins Oct. 1. The compromise on financing for antisatellite testing was worked out by Senators Paul E. Tsongas, Democrat of Massachusetts, and John W. Warner, Republican of Virgina, after a nearly three- hour secret session. Request by Reagan Mr. Reagan has asked for about $2 billion in fiscal 1985 for research on methods intended to defend the United States from Soviet nuclear ballistic missile attack. He has made a separate $400 million request for development of a rocket-powered missile designed to destroy Soviet satellites in space.

The Supreme Court ruled today that a court may not order an employer to protect the jobs of recently hired black employees at the expense of whites who have more seniority. The 6-to-3 decision came in the most highly charged case involving alleged discrimination against whites to reach the Court in several years. In an opinion by Associate Justice Byron R. White, the Court overturned an order by two lower Federal courts that had shielded newly hired black officers in the Memphis fire department against layoffs. The Court's ruling comes at a time of continuing debate between union leaders, who say senority should determine who is laid off, and civil rights leaders, who say such a policy frustrates the employment prospects of minorities. It is likely to have some impact in many cities across the nation where similar cases are in litigation.

At least 12 more Sikh deserters from the Indian Army were reported killed today and nearly 350 more were arrested. Military officials declared the scattered three-day revolt by Sikh troops to be at an end, but 200 members of a Sikh battalion in the northeastern state of Tripura stole four military vehicles and deserted today. They were intercepted and, according to officials, surrendered without a fight. ''Only stray cases of individuals remain to be mopped up,'' said Brig. K. L. Juneja, an army spokesman. He said that all other deserters had surrendered, been captured or killed.

TO many parents, the best baby sitter is another parent. This philosophy is the one behind the baby-sitting cooperatives in the city that allow parents to provide child care and pay each other back in kind. Peace of mind is one advantage of a co-op, especially for new parents who hesitate to leave an infant with a teen- ager. The money they save is another. And for the children, a few hours with a neighboring family can be like a play date. Some cooperative baby-sitting groups use a special currency, such as poker chips or computer cards that are worth a certain amount of time. When parents baby-sit, they are ''paid'' with this currency, and they can ''spend'' it on sitters for their own children. Other co-ops have an elaborate bookkeeping system and a secretary, or ''central,'' who keeps track of each family's balance of hours.

''Let's just get together and talk about the general world situation, 'cause we've got to figure out some way not to blow each other up.''

An article on the American Museum of Natural History yesterday misstated the trustees' position on a statement to accompany ''Ancestors,'' an exhibition that includes fossils from South Africa. The board will post a statement saying the exhibition ''demonstrates the common ancestry of all humans and the irrationality of racism.''

A divided International Trade Commission found today that the American steel industry was being seriously injured by imports and that trade barriers should be raised to protect a number of its major product lines. If protection against steel imports is granted, prices would rise, according to American steel executives. The commission, an independent agency with jurisdiction over the nation's trade laws, ruled in one of the most politically sensitive trade cases in years. It acted on petitions to find that the volume of steel imports was injuring the domestic industry.

THERE is a fresh excitement to the subject of fish and fish cooking these days. It comes partly from health considerations, as more people recognize the importance of fish in a healthful diet; partly from greatly increased availability all over the country in the last few years of a wider variety of fish, and partly from a new understanding of an old truth, that fresh fish, simply prepared, is a delightful item on any menu, whether the home cook's or the restaurateur's. ''The fresh market is the growing market,'' said Paul Johnson, a San Francisco Bay area fish dealer. ''With airline connections all over the world now, we can have fish in the market within 12 hours of its being killed.'' Mr. Johnson took A list of fish now in season and recipes are on Page C8. over the Monterey Fish Market five years ago, ''when it was just me and a truck on the San Francisco pier,'' he said. Since then his business has grown 20 times over, and he now has 12 employees in two locations.

East-West summit talks were urged by two Senate Republican leaders because relations are so tense. The urgent appeal was made to President Reagan by the Senate Republican leader, Howard H. Baker Jr., and Senator Charles H. Percy, chairman of the Foreign Relations Committee. However, the Administration reiterated its view that any meeting between Mr. Reagan and the Soviet leader, Konstantin U. Chernenko, should be carefully prepared and offer the prospect of tangible results. (Page A1, Column 1.) At least 12 more Sikh deserters from the Indian Army were reported killed and nearly 350 more were arrested. Military officials in New Delhi said the scattered three-day revolt by Sikh troops was ending. (A1:1-3.)

YOUR mother may have told you that fish was ''brain food'' (and there is now evidence she may have been right), but folk wisdom missed a valuable asset of fish that medical scientists have only recently discovered: its apparent protective effect on the heart and blood vessels. Ironically, the very same fatty fish and shellfish that in the past you've been urged to avoid for the sake of your heart now seem to be the most helpful. For fish oils have been found to contain fatty acids that can lower harmful fats and cholesterol PERSONAL HEALTHin your blood and can reduce the tendency of blood cells to form artery-blocking clots. The net result may be a diminished risk of heart disease and stroke. The new findings also suggest that human beings may actually require these fatty acids in their diet. Without them, certain organ systems - the brain, in particular - may fail to develop properly.