What was going on when I was born?

State and city medical investigators and review committees at Lincoln and Coney Island Hospitals began simultaneous inquiries yesterday into charges by striking physicians-in-training that two patients died needlessly because of staff shortages. The inquiries got under way as the strike by the physicians against seven of the city's 16 municipal hospitals and two private, voluntary hospitals continued for the third day yesterday. In one of the deaths, Dr. Elliot Gross, the city's Chief Medical Examiner, reported last night that an autopsy yesterday showed causes for dying other than the one reported by the hospital.

President Reagan's proposed budget cuts would reduce the disposable income of poor workers who also receive welfare by so much that their families would be little better off than those who relied entirely on public assistance, according to the first comprehensive study of the potential effects on individual families on welfare. The report, by the University of Chicago Center for the Study of Welfare Policy, examined the aggregate impact that proposed reductions in six Federal programs would have on representative poor families in 10 states, including New York. The center, which is based in Washington, is directed by Thomas C.W. Joe, who was a ranking welfare official in the Nixon Administration and is the principal author of the new study. The center has the reputation among social scientists as being one of the most reliable sources of nonpartisan information on welfare matters. Edwin L. Dale Jr., a spokesman for the Office of Management and Budget, said today that he could not comment on specific points of the study because he and his colleagues had not seen it, but he did not dispute the study's methodology or its statistical findings. He said that the Administration had not done a state-by-state analysis of the potential impact of the proposed budget reductions on individual families.

OPERAGOERS with a taste for the offbeat will be treated to a generous selection of novelties in this opera-rich city over the weekend when a particularly varied selection of works outside the standard repertory are offered by the companies in residence. Back in the old days, 25 to 30 years ago, the City Opera was a haven for the adventurous. But after its move to Lincoln Center in 1966, the company began more and more to stage the same warhorses that dominated the repertory across the plaza at the Metropolitan Opera. Beverly Sills seems to be changing all that, if the operas being presented at the State Theater this weekend are any indication of the City Opera's present policy. Not one of them can be considered bread-and-butter fare - in fact, 30 years ago the very notion of seeing Verdi's ''Attila,'' Donizetti's ''Maria Stuarda'' or Handel's ''Giulio Cesare'' in a major New York opera house would have been unthinkable. Now, all three operas have come back to us, thanks to the so-called bel-canto revival, ''bel canto'' in this case referring to almost any onceforgotten Italian opera composed between 1600 and 1850. ''Attila'' represents the last flourish of this school, one of the works Verdi wrote before he reached his mature style in the operas from ''Rigoletto'' to ''Falstaff,'' a sequence of masterpieces that have never left the repertory.

Harold J. Smith, the boxing promoter who has been accused by the Wells Fargo National Bank of defrauding it of $21.3 million, asserted last night that at least four bank officials were involved who have not previously been mentioned in connection with the alleged fraud. In his first face-to-face interview since he went into hiding two months ago, Mr. Smith, the chairman of Muhammad Ali Professional Sports Inc., which is known as Maps, declared in an interview that he was innocent of any wrongdoing and gave an account of the situation that differed substantially from the bank's. A spokesman for the bank, asked about all the new assertions today, said the bank would have no comment. The $21.3 million loss was disclosed by Wells Fargo in a lawsuit filed here Feb. 2. The bank accused a group of sports promoters and companies of defrauding it of the money ''by internal manipulation of funds'' involving 14 separate accounts.

A picture caption in some copies of The Times on Wednesday incorrectly identified a lawyer, E.D. Bronson Jr. Mr. Bronson, of Bronson, Bronson & McKinnon, is the lead attorney for the entertainer Carol Burnett in her case against The National Enquirer. An article Wednesday in Business Day gave an incorrrect age for the Washington law firm of Surrey & Morse. The firm was founded in 1950.

International An effort to develop an anti-Soviet belt across the Middle East will be pressed by the Reagan Administration, according to Secretary of State Alexander M. Haig Jr. The aim, he said in Senate testimony, will be a strategic ''consensus'' stretching from Egypt to Pakistan, and including such disparate nations as Turkey, Israel and Saudi Arabia. (Page A1, Column 6.) Bonn officials welcomed disavowals by Washington of statements by a Reagan Adminstration security adviser that questioned the ability of West Germany's Foreign Minister to withstand Soviet pressure and suggesting that war with the Soviet Union was inevitable unless the Russians abandoned Communism. (A3:1-3.)

''We feel it is fundamentally important to begin to develop a consensus of strategic concerns throughout the region among Arab and Jew and to be sure that the over-riding danger of Soviet inroads into this area are not overlooked.'' - Secretary of State Alexander M. Haig Jr. (A4:3.)

A Cabinet-level task force briefed President Reagan today on its recommendations for aiding the depressed auto industry. But its members were still split over whether to ask Japan to limit car exports to the United States. James S. Brady, the White House press secretary, said the group had reached a consensus on a basic approach to the problem, but he declined to say whether this meant that all members were agreed on the need to seek import restraints. Three Choices Offered An Administration official who attended the 55-minute meeting said that three trade options were presented: - Pursuing various diplomatic signals from Japan regarding its possible willingness to consider voluntary restraints.

The space shuttle Columbia passed another crucial milestone in its preflight preparations yesterday, but the successful countdown rehearsal in Florida was marred two hours later by an accident that left one technician dead and two others injured, one critically. The technicians were exposed to the pure nitrogen atmosphere in an enclosed area around the engines inside the shuttle. The nitrogen is used to drive out the oxygen present in normal air, lessening the chance of a fire or explosion in the engine area. The death was caused by a lack of oxygen.

A plant to treat hazardous waste, proposed for construction in New York State within the next six years, will not be able to dispose of all of the hazardous chemical wastes generated in the state, the chief of a lobbying group for business interests said today. The lobbyist, Raymond T. Schuler, heads the Business Council of New York, representing 4,000 companies. He spoke at a news conference called to release the findings of a study on disposal of hazardous wastes, conducted by the Public Policy Institute for the Business Council.

A Cabinet-level task force on aid to the auto industry remains split over whether to seek restraints of auto imports from Japan. A White House spokesman said further talks would be held, and that President Reagan wanted to discuss the issue with key legislators next week. (D1.) In Tokyo, Japan's trade minister said his country might have to mandate cutbacks in auto exports to the U.S., rather than rely on voluntary reductions, in order to avoid private antitrust suits in the U.S. (D4.) The U.S. current trade account had a $118 million surplus in 1980, its first since 1976, and a $687 million surplus in the fourth quarter, the Commerce Department said. (D1.)

The First Boston Corporation, one of Wall Street's most prominent investment banking houses, emerged yesterday as the marriage broker that brought together the Prudential Insurance Company of America, the nation's largest insurance company, and the Bache Group Inc., the parent of Bache Halsey Stuart Shields, the nation's eighth-largest brokerage house. Robert A. Beck, Prudential's chairman and chief executive, said in an interview that the idea for the $385 million purchase of Bache originated with First Boston. He added that he did not know the fee that the Wall Street concern would be paid - by Bache - but it was reliably estimated to be more than $1 million. Belzberg Bid Was Resisted Prudential's proposal to acquire Bache for $32 a share, an offer it quickly accepted, apparently ended the efforts of the wealthy Belzberg brothers of Canada to acquire Bache, an effort bitterly opposed by its management. ''We would like to have done it, but it's out of our hands now,'' Hyman Belzberg, the eldest of the three brothers, said in a telephone interview from Calgary, Alberta. The Belzbergs had acquired 22.6 percent of Bache's nearly 11 million shares since 1979, at prices between $8 and $21 a share and had sought seats on Bache's board.