What was going on when I was born?

The Justice Department today rejected the New York State Legislature's plans to reapportion Congressional, State Senate and Assembly districts on the ground that they discriminated against minority groups in the Bronx, Brooklyn and Manhattan. The action caught New York State politicians by surprise, and Governor Carey immediately signed a bill postponing the state's primary from Sept. 14 to Sept. 23. The bill also delays from today until July 6 the date when candidates can begin collecting signatures for nominating petitions. Voting Rights Act Involved The districts of the three counties -Bronx, Kings and New York - are subject to review by the department to determine the effect of reapportionment on minority representation. The three counties fall under the department's jurisdiction because less than 50 percent of their eligible voters are registered. The Voting Rights Act of 1965 presumes that when this is the case the rights of minorities may be violated.

A man who was given a conditional discharge from prison last December was arrested yesterday and charged with the murder on Monday of two insurance executives in an office tower in Manhattan's financial district. Detectives found the suspect, according to the police, through a job resume that had apparently fallen from his pocket as he struggled with his victims in a men's room in the office tower. The two men - one an office manager and the other an insurance underwriter for different companies - were shot and slashed to death Monday afternoon when they apparently resisted being robbed, the police said. The arrested man was identified as Nathan Dodell, 28 years old, of 557 West 150th Street in Manhattan, who gave his occupation as temporary office worker.

ESPITE the fact that America is supposed to be in the midst of a regional cooking renaissance, we are still a nation of strangers where many native dishes are concerned. Most Northerners, for instance, have not developed a passionate hunger for crawfish bisque and crawfish etouffee, any more than Southerners have for pastrami on rye or lox and bagels. And Northerners can no more understand the Southern craving for biscuits and country ham with ''red eye gravy'' than a Southerner like myself can comprehend the New Englander's enthusiasm for redflannel hash. There are a couple of Southern specialties that I would love to convince Northern eaters about just because they are so delectable: whole hominy and grits. Both are closely related to cornmeal, which is enjoyed in the South and out of it. In that they all derive from the same base - dried kernels of corn, whole or ground - it is scarcely surprising that they team notably well with grated cheese and chilies. Cornmeal, of course, has widespread uses. In the form of polenta it is considered one of the great specialties in certain regions of Italy, notably Piedmont, Lombardy and Veneto. Masa harina, a finely ground version of cornmeal, is treasured throughout Mexico and is best known as the basis for tortillas.

The Democratic-controlled House today grudgingly approved a Republican-sponsored budget compromise, which one supporter acknowledged ''may be nobody's cup of tea, but the only cup of tea we have.'' The vote was 210 to 208. The House thus completed action on the final version of the first budget resolution for the fiscal year 1983, ending a tumultuous fivemonth debate whose outcome was often in doubt. If a second budget resolution is not approved, an outcome that is considered likely, the first budget resolution will become binding in September.

The Democratic State Committee today designated Alfred B. DelBello, the Westchester County Executive, as its favored candidate for lieutenant governor and qualified two others to run for the same post in the September primary. The two others are John S. Dyson, chairman of the State Power Authority, and former State Senator Carl McCall. The party leadership also named Attorney General Robert Abrams to run in the primary for re-election.

''There must be an end to the doctrine that allows so many persons to commit crimes of violence, to use confusing procedures to their own advantage, and then to have the door opened for them to return to the society they victimized.'' - Attorney General William French Smith, on Hinckley acquittal. (B6:1.)

Minutes before 10 A.M. yesterday, officials from National Utilities and Industries entered the crowded trading floor of the New York Stock Exchange, where N.U.I. was getting ready to be listed on the Big Board for the first time in the company's 127-year history. John Kean, N.U.I.'s lithe, mustachioed president, found the going tricky. It is barely possible to breathe on the floor, an untidy labyrinth where the stocks of America's major corporations are traded. New ones join and old ones leave on about a weekly basis. N.U.I. was the 32d listing this year and was neither more nor less momentous than the others.

Gold closed yesterday in New York below $300 an ounce for the first time in nearly three years as high interest rates continued to depress bullion prices. After rallying in London by $7.50 an ounce to $304 at the afternoon fixing there, gold began declining shortly afterward in New York. When New York's Commodity Exchange closed, gold was down $3, at $298. In later trading at the Republic National Bank and other dealers, gold was bid at $297.75 an ounce, down $2.25 from Monday. It was the first time that gold had closed below $300 an ounce since Aug. 20, 1979.

Consumer prices rose 1 percent in May, the Labor Department reported today, pushing the Consumer Price Index back to a double-digit annual rate and halting, at least temporarily, this year's surprisingly good news on inflation. The sharp increase in the index, which translates to a compound annual rate of 12 percent, follows small rises and one decline in the last four months. It was the largest monthly increase since last September. Last month's spurt in prices was powered by a rise in gasoline prices, which had been declining sharply until May, one of the key reasons for the low 1.5 percent annual rate of inflation through April. A somewhat mystifying rise in home prices and a jump in food prices also contributed to the May increase.

''THIS business is like fashion, with everyone following the latest idea,'' said Jean-Paul Grasmuck, director of sales and marketing for a major cheese importer. And right now in cheeses, blue is big. Imports to the United States of blue cheeses totaled about 5 million pounds last year, an increase of 633,000 pounds over 1980. For years blue-veined cheeses, especially Roquefort, were regarded more as ingredients for salad and other dishes than as table cheeses. But now the variety of blue cheeses available has greatly expanded, particularly in the New York area, and that attitude is changing. On the cheese tray the blues provide a contrast of color and brightly assertive flavor to compliment other varieties. There is simple, classic elegance to the wedge of rich Stilton served with a glass of Port at the end of a dinner, or some pungent Gorgonzola to complement a luscious ripe pear. The blue cheese of the moment is what importers and retailers have been calling ''blue-veined Brie,'' a cross between the traditional blue cheese of the Roquefort type and a soft-ripening Camembert or Brie style. It is buttery and smooth, with a mild flavor given a touch of sharpness by the blue veining.

LAST week the National Academy of Sciences issued a report entitled ''Diet, Nutrition and Cancer,'' which informs adults, in effect, that if they want to live longer they ought to pay attention to what their mothers told them to eat when they were children. The academy's advice, the result of a two-year review of research by 14 scientists, is aimed at reducing the risk of cancer through proper nutrition. Though it may be couched in official terms, it is no more threatening than the familiar words most adults can recall: ''Eat your broccoli.'' ''You can't have a cupcake before dinner.'' ''Must you put so much butter on your bread?'' Some of the dietary changes have been proposed before - reduced intake of fat, increased consumption of fruits, vegetable and whole grains, moderate drinking of alcohol -because scientists believe that they can reduce the risk of cardiovascular diseases. This is the first time, however, that a scientific body, the academy's National Research Council, has made the recommendations because it believes, as the report says, that they are ''likely to reduce the risk of cancer.''

John W. Hinckley Jr. was committed today to a Federal mental hospital for psychiatric examination to determine whether he should go free, amid a chorus of outrage from Reagan Administration officials and others at his acquittal Monday evening. At the same time, two members of the jury of 12 that unanimously found Mr. Hinckley not guilty by reason of insanity said today that they thought he had been guilty and would have convicted him, but had been worn down by other jurors. Federal District Judge Barrington D. Parker issued a written order today providing that the 27-year-old loner who shot President Reagan and three other men on March 30, 1981, ''be committed forthwith'' to St. Elizabeths Hospital. The judge set Aug. 9 for a hearing on whether Mr. Hinckley ''is entitled to release from custody.'' What Hospital Must Do Judge Parker, who presided at the eight-week trial that ended by stunning the courtroom audience and the nation, said that the hospital staff must determine ''whether he is presently mentally ill or whether he has recovered his sanity, and whether he will not, in the reasonable future, be dangerous to himself or others.''