What was going on when I was born?

A dispatch and an accompanying table yesterday on a poll surveying the views of Roman Catholics in America misstated one finding. The percentage of all Roman Catholics favoring the current status of legal abortion was 26, not 36.

Executives of the National Gypsum Company offered yesterday to buy the big supplier of building products for about $1.1 billion in cash and securities and then make it a private company. The leveraged buyout proposal, which was submitted to directors, calls for the investor group to pay $40.50 in cash plus $17 in debentures for each of Gypsum's 22.8 million shares. Traders, pointing out that the debentures paid no interest for the first five years, valued them at only about $9.50, which would make the offer worth about $50 a share. At that price, Gypsum's 22.8 million shares would be worth $1.1 billion.

A former communications specialist for the National Security Agency was arrested this morning after admitting that he sold American intelligence secrets to the Soviet Union for more than five years, the authorities said. Federal officials said the suspect, Ronald W. Pelton, 44 years old, was identified as a spy by Vitaly Yurchenko, the turnabout Soviet defector who fled to the West last summer but returned to Moscow early this month. In Mr. Pelton's case, an official said, evidence was found to support Mr. Yurchenko's allegations. Mr. Pelton told the Federal Bureau of Investigation in an interview Sunday that he met with a Soviet intelligence officer several times from January 1980 through January 1983, according to a bureau affidavit filed in Federal District Court today. It said the spying went on until September of this year.

IN a major catastrophe like the Mexican earthquake and the mud slides in Colombia, experts say, the psychological world collapses just as resoundingly as the physical one. The most prominent psychological casualty is the sense of invulnerability with which most people manage to face the risks of daily life. Also shattered, psychologists are finding, are a person's sense that his or her world is comprehensible and has meaning, and for many years after the trauma a person's very sense of worth may be damaged. ''The common belief that people recover after a few weeks from disaster is based on mistaking denial for recovery,'' said Dr. Mardi Horowitz, a psychiatrist at the University of California medical school at San Francisco. Delayed Psychological Reactions Dr. Horowitz's research has shown that many psychological symptoms do not appear until long after the victim seems to have fully recovered from the disaster, and when the problems do arise - such as difficulty concentrating, depression or sleeplessness - their causes may go unrecognized.

The Sperry Corporation said yesterday that it had negotiated several agreements with Hitachi Ltd. to evaluate ''technology exchanges'' between the two companies, leading industry experts to speculate that the Japanese electronics giant will soon be manufacturing key components of Sperry's mainframe computer systems. The move appears to be another in Sperry's transformation away from manufacturing much of its own hardware, primarily because of heavy price competition from the International Business Machines Corporation and Japanese manufacturers. Already, another Japanese company, Mitsubishi, manufactures Sperry's personal computers.

A table in Business Day on Saturday with an article about leveraged buyouts included an erroneous identification supplied by Merrill Lynch Capital Partners for one company. The Union Texas Petroleum Corporation, not the Texas Eastern Corporation, was sold in a leveraged buyout.

The water level in New York City's reservoirs has risen sharply in the last month, city officials said yesterday, but they cautioned against optimism that the water shortage was nearing an end. After a weekend with periods of rain, the reservoirs were reported to be at 62.1 percent of capacity yesterday, an increase of 10 percentage points since the end of last month, but still below the normal level for the day of 72.6 percent. Since September, when the reservoirs hit a low of 44 percent of capacity, the level has risen steadily. But city officials were reluctant yesterday to talk about easing restrictions on water use.

The death toll in the hijacking of an Egyptian airliner rose to 60 today as passengers and others questioned the way in which Egyptian commandos had carried out an armed rescue attempt. The Maltese Government said that of the 60 who were killed, 57 had died in the storming of the Egyptair Boeing 737 on the tarmac here on Sunday night. Officials said that of the 98 people now thought to have been on the plane when it was hijacked on Saturday, only 38 survived. Hijacker Is in Hospital At the same time, the Maltese Government announced that one hijacker had survived the assault and was being treated in a hospital, where he was reported to be unconscious. A Government spokesman, saying it was unclear whether the man would survive, said no decision had been made on a trial or extradition.

A state appeals court panel, in an unusual departure from its own strict secrecy rules, ordered yesterday that details of disciplinary proceedings against Roy M. Cohn be made public. The panel ruled that Mr. Cohn, a politically prominent Manhattan lawyer, had in effect waived his right to confidentiality by publicly accusing a court-appointed disciplinary committee of, in the panel's words, ''having been constituted of incompetents who prosecuted him for a political purpose, upon meritless charges, with the intent of 'smearing' him.'' Mr. Cohn ''may not both publicly attack the committee panel for having corruptly prosecuted him and closet from public view the record of the proceeding before the committee,'' a five-judge panel of the Appellate Division of the State Supreme Court ruled unanimously. ''Such an advantage,'' it said, ''leaving the target of an attack helpless, is not favored by the law.''

A development team that includes William Zeckendorf Jr. announced plans yesterday for a $500 million office and housing complex on the site of the old Madison Square Garden on the West Side of Manhattan. The chief commercial tenant for the project, which is still subject to a rigorous city approval process, would be Ogilvy & Mather Worldwide, the country's fourth largest advertising agency. It announced its intention to relocate from several sites in Manhattan. The plan for the four-acre site - the entire block bounded by Eighth and Ninth Avenues and 49th and 50th Streets - calls for a 45-story office tower on Eighth Avenue, a 38-story condominium tower to the west and several six- and seven-story residential buildings fronting on Ninth Avenue. The site, which from 1925 to 1968 housed the third version of Madison Square Garden, is now a parking lot.

A BRIEF sentence in the joint Soviet-American statement issued after last week's summit meeting could give a new spur toward development of an exotic, potentially inexhaustible energy source that has fallen out of political and budgetary favor in recent years: controlled thermonuclear fusion. At first glance, the notion that President Reagan and Mikhail S. Gorbachev, the Soviet leader, would endorse an international effort to develop one particular form of energy, nuclear fusion, above all others might appear odd. But the proposed cooperative effort in fusion actually fits the needs and capabilities of both superpowers quite well. It is also consistent with an emerging recognition that enormously expensive, long-range technical projects virtually require some form of international cooperation. Individual nations, in many cases, can no longer afford to build multibillion-dollar facilities that will essentially duplicate similar costly facilities built elsewhere. Both nations have much to contribute and much to gain from collaboration in fusion. The Soviet Union pioneered the development of the most thoroughly studied proposed fusion reactor, the ''tokamak,'' and has the largest body of trained fusion workers in the world. The United States has many of the world's leading fusion scientists and is said to have pulled ahead of the Russians by building somewhat larger and more advanced experimental fusion machines. However, the Soviet Union has a new device under construction in Moscow that would further increase its capabilities.

International The death toll in the hijacking of an Egyptian airliner to Malta rose to 60 as passengers and others questioned the way in which Egyptian commandos had carried out an armed rescue attempt. The Maltese Government said that of the 60 who died, 57 were killed in the storming of the Boeing 737 on the tarmac in Valletta, Malta. [Page A1, Columns 4-6.] Three people shot execution-style by the hijackers of Egyptair Flight 648 survived. Patrick Scott Baker, 28 years old, of White Salmon, Wash., played dead after being shot at point-blank range. Jackie Nink Phlug, 30, of Pasadena, Tex., lived because the bullet did not hit her brain. Tamar Artzi, 24, of Israel, escaped death ''by .05 centimeters,'' her doctor said, when the bullet fired at her head only nicked the tip of an ear. [A1:4-5.]