What was going on when I was born?

Treasury Secretary Donald T. Regan is preparing two sweeping tax reform proposals for possible inclusion in President Reagan's State of the Union address, although legislation to put them into effect might be delayed until 1984, Administration officials said today. Both proposals would broaden the tax base and close loopholes, which many Republicans and Democrats have advocated, and would make it possible to increase tax revenue while lowering tax rates, the officials said. One of the proposals under consideration would replace the graduated income tax with a flat-rate tax system. Such a system would tax income at a single fixed rate, or several fixed rates, without most of the deductions that are now available to reduce taxable income, the officials said.

Dr. Barney B. Clark's condition has improved to the point where he might leave the hospital as early as three weeks from now, but with ''significant lung and kidney impairment,'' his doctors said today. Dr. Clark is ''significantly more lucid, communicating more and physically stronger,'' Dr. Chase N. Peterson, vice president for health sciences at the University of Utah Medical Center, said at a news conference. Dr. Clark became the world's first recipient of a permanent artificial heart 41 days ago. The Jarvik-7 artificial heart has been working well and there is no evidence of infection, the doctors said. At the news conference, the first in two weeks, Dr. Peterson and Dr. Lyle Joyce, one of Dr. Clark's doctors, left an impression of cautious optimism, with more emphasis on the optimism.

The nation's leading banks, in an action that lagged considerably behind a sharp drop in the cost of their own funds, lowered their prime lending rates yesterday by half a percentage point, to 11 percent. The banks attributed the delay to uncertainty about the cost of new money market accounts for consumers and the possibility of large losses from loan defaults. The prime rate cut was widely expected because of the unusually big gap between the interest rates banks have been paying for their own funds, about 8 1/2 percent, and the interest rates they have been charging on loans to their medium-size and small corporate customers, which range upward from 11 1/2 percent. In response to the falling cost of money, the Chase Manhattan Bank lowered its prime rate to 11 percent as early as Dec. 28, but no other major bank followed until yesterday.

The first known theft of secret data on the nation's money supply from the Federal Reserve Board's computers was discovered because an alert employee questioned the apparent use of the computer by a fellow employee who was then on vacation. Details of the theft and subsequent attempts were disclosed today in Federal District Court here when Theode C. Langevin, a former Fed employee, pleaded guilty to tapping illegally into the central bank's computer on his first day as a ''Fed watcher'' at the E.F. Hutton brokerage firm in New York. Discovery of the first theft, on the night of Nov. 22, 1982, was fortunate, said an Assistant United States Attorney, William S. Block. He said that on the morning of Nov. 23, Carol Keyte, an employee in the same division where Mr. Langevin had worked, noticed that the last recorded use of the computer was by Wayne Smith, who was registered by his name and used the secret password ''PAZ.''

Secretary of Defense Caspar W. Weinberger announced today that he had recommended to President Reagan an $8 billion reduction in military spending proposed for 1984 to help cut the projected Federal deficit of about $200 billion. ''In response to economic problems,'' Mr. Weinberger told reporters at the Pentagon, ''we have agreed before, as we agree now, to modifications in our original program to rearm America.'' President Reagan, speaking in Dallas, asserted that ''we are not reversing our course'' on increasing military power. The President contended, ''It is not setting back in any substantive way at all our defense program, because that still remains our top priority.'' Tepid Reaction in Congress Initial Congressional reaction was tepid, with supporters of increased military spending expressing disappointment and advocates of smaller military budgets asserting that the cut was not enough.

The robotics industry, squeezed by competition and a recessionbattered market, is bracing for a shakeout. Some industry leaders think it has already begun. Analysts who follow high-technology industries have said that many small robot manufacturers are doomed by the recent move into robotics of such industrial giants as the International Business Machines Corporation and the Westinghouse Electric Corporation. Last month Westinghouse announced its acquisition of Unimation Inc., the nation's largest robot maker, for $107 million.

Leading banks, in an action that lagged behind the drop in the cost of their funds, lowered their prime lending rates by half a point, to 11 percent. They cited doubts about the cost of new money market accounts and the possibility of large losses from loan defaults. The banks had been paying about 8 1/2 percent for their funds and charging corporate customers 11 1/2 percent and more. (Page D1.) Two sweeping tax reform proposals are being prepared by Treasury Secretary Donald T. Regan for possible inclusion in the President's State of the Union address. One concerns a flat-tax system; the other would concentrate on taxing spendable income and exclude savings and similar investments. (D1.)

Nine men, including four New York City police officers, were accused in a Federal lawsuit yesterday of fraudulently obtaining more than $1 million in profits by using ''insider'' information to buy and sell stocks. The suit was filed by the Securities and Exchange Commission in Federal District Court in Manhattan. The S.E.C. asked for court orders requiring the defendants to return all the profits and prohibiting them from violating the securities laws.

Secretary of Health and Human Services Richard S. Schweiker has resigned to take a job with the American Council on Life Insurance, an industry trade association, the White House announced tonight. Formal letters of resignation from Mr. Schweiker and acceptance by Mr. Reagan are to be made public Wednesday, a White House official said. White House officials said they would have no comment on the resignation, which took several of them by surprise. But theysaid Mr. Schweiker had not left for policy reasons.

''We've done this before and I'd rather take my chances with someone I've been down the road with before rather than someone new.'' - George Steinbrenner discussing Billy Martin. (A1:3.)

Fifteen men, including a Hackensack police officer, were arrested yesterday in a series of raids in northern New Jersey that culminated a 10-month investigation into the sale of illegal firearms and explosives. In the course of their investigation, undercover agents spent $14,500 to buy 30 firearms, including a British-made 9-millimeter Sten machine gun. They also purchased 15 pounds of plastic explosives and two silencers.

IN the kitchen or anywhere else, for that matter, Koei Hoshino is a colorful presence. Tall and sturdily built, clothed in a billowy purple and white robe, her head shorn as part of the ritual of her vocation, she is assistant abbess of the @Sanko-in Zen Buddhist temple in Koganei, on the outskirts of Tokyo. She is also a master of shojin ryori, a style of vegetarian cookery with a tradition that dates back more than 600 years. ''Shojin cooking is the food that is eaten by the monks and nuns in Buddhist temples,'' Koei Sensei, as she is addressed - ''sensei'' means ''teacher'' - explained through a translator dur-ing a recent visit to this country. ''It is said to derive from imperial court cuisine and was reputedly brought to Japan by a Chinese priest. It was the custom, prior to his arrival, for the members of the sect to go out and beg for rice in the streets. This priest was the first person to have all the monks eat together in a temple.'' If vegetarian cookery can be classified as unconventional, then the shojin meal that Koei Sensei prepared for me and several guests was one of the most interesting, gratifying and delicious unconventional menus I can recall sampling. It included a radish and bean curd soup (the base of which is dashi made with seaweed and mushrooms); a well-flavored eggplant dish with miso (soybean sauce), and a small platter of fresh okra briefly cooked and flavored with sake and light soy sauce.