What was going on when I was born?

THE anguish that leads to suicide seems to follow no set path. But researchers believe they are making important progress toward understanding that painful process. They have identified a deficiency of a specific chemical - serotonin - in the brains of some people who are prone to take their own lives in the face of life's difficulties. Some researchers believe as a result that biological factors may play a far greater role in the events that end in suicide than has been realized. And the hope now is that a drug could eventually be developed to correct the chemical deficiency and prevent at least some future suicides.

Columbia University's board of trustees voted yesterday to sell, ''in an orderly way'' over the next two years, virtually all of the university's $39 million in stock in American companies doing business in South Africa. Columbia thus became the first Ivy League school to join the growing roll of colleges, state and local governments and other institutional investors that have chosen divestment to protest South Africa's racial policies, known collectively as apartheid. The divestment, to be completed by October 1987, will involve the sale of about 4 percent of Columbia's $900 million portfolio, and will include stock in such companies as American Express, Burroughs, Chevron, Coca-Cola, E.I. du Pont de Nemours, Ford Motor, General Motors, International Business Machines, Mobil Oil, Phillips Petroleum and Sperry. Vote at Closed Session Consideration will be given to ''appropriate exceptions,'' such as stock in news-media companies with bureaus in South Africa, the board said. The vote was taken at a closed session of the 24-member board and the tally was not announced, as is customary.

Heavily armed men hijacked an Italian cruise ship with more than 400 people aboard in the Mediterranean on Monday and demanded the release of 50 Palestinians from Israeli prisons. The leader of the hijackers, reportedly members of a militant Palestinian faction, was said to have warned that the first hostages to be killed would be Americans. It was unclear how many Americans were still on the ship. A spokesman for the cruise line said from California on Monday night that 62 Americans had been registered for the cruise. An Italian Foreign Ministry report said 72 Americans were listed as passengers.

International Commandos hijacked a cruise ship with more than 400 people aboard in the Mediterranean. The heavily armed hijackers, identified as Palestinians, demanded the release of 50 Palestinian prisoners being held in Israel. The leader of the commandos was quoted as saying that the first hostages to be killed would be Americans. Unconfirmed reports on the state-run Italian television said that 28 Americans were on board the Italian cruise ship. The hijackers were quoted as saying they would blow up the vessel if a rescue mission was undertaken. [Page A1, Columns 4-6.] Major aid for drought-stricken nations of sub-Saharan Africa is set. Financial leaders from around the world agreed to set aside $2.7 billion from the International Monetary Fund for a special lending pool to help the poorest countries promote economic growth. Countries eligible for the loans are those whose average per capita income is below $410 and that have problems paying off bank loans and generating enough foreign currency to pay for key imports. [A1:1.]

In the aftermath of rioting in the north London district of Tottenham in which a constable was killed, the police warned today that they would be prepared to use plastic bullets and tear gas in future confrontations with rioters. The Home Secretary, Douglas Hurd, said the police would have the Government's ''full support'' if they found it necessary to resort to new methods of control. ''It is absolutely vital that the police have the equipment they need,'' he declared. In fact, riot policemen were reported to have been armed early today with both plastic bullets and gas canisters - which have yet to be used in a civil disturbance in Britain - when they swept through the Broadwater Farm housing project just before dawn. They met no resistance, however, from the racially mixed crowd of youths that had been driven back during the night onto the grounds of the project and contained there.

The 34-acre site on Staten Island -strewn with rubble, its piers rotting -hardly seems the center of a controversy involving talk of war and peace and nuclear missiles. But it is there, on Upper New York Bay a mile and a half north of the Verrazano-Narrows Bridge, that the Navy plans to build a $300 million base for seven ships, all of which are capable of carrying nuclear weapons. Supporters of the base acknowledge that it is likely that at least some of the seven ships would actually carry such weapons. And therein lies a citywide debate with national implications: Should the Navy establish a base in New York City for warships that could launch nuclear weapons? 'Defending the United States' ''If someone said at a party, 'Let's bring nuclear missiles into the densest metropolitan area of the country,' you'd think it was a joke,'' says Thomas DeLuca of Mobilization for Survival, an antinuclear group that collected 111,954 signatures to put a referendum seeking to block the base on the Nov. 5 ballot. ''It defies common sense.''

Two accidents involving infants who suffered disfiguring burns while undergoing circumcisions at an Atlanta hospital have focused concern on a traumatic modern complication of an ancient surgical procedure. According to lawsuits filed in behalf of the two children, the infants suffered severe electrical burns to the penis and adjacent areas when physicians, in separate incidents on the same day, used an electric cauterizing needle as part of the circumcision procedure. The burns to one of the infants were so severe that his penis was destroyed. A sex change operation has been performed so that the child will be raised as a female, according to a lawsuit filed on behalf of the child's parents, who are identified only as Mr. and Mrs. John Doe. Both the physicians and officials at Northside Hospital, where the accidents occurred, have refused to discuss what went wrong.

The Treasury Department, trying to put pressure on Congress to raise the Government's debt ceiling and pass a companion bill calling for a balanced budget by 1991, said today that as early as Tuesday the Government would order banks not to honor its own checks. The Reagan Administration, which supports the bill to balance the budget, made the threat as Republican and Democratic leaders in Congress maneuvered to achieve advantage from the deficit issue. Linking the Issues Political maneuvering on the debt ceiling began last week when the Republican leadership in Congress backed a move in the Senate to offer the budget-balancing proposal as an amendment to the bill to increase the debt ceiling. The bill gives the Government the authority to borrow money, generally through bonds and notes. The ceiling, which is now $1.8 trillion, would need to be raised to just over $2 trillion to accommodate Government borrowing to cover the deficits accumulated over the years. . While Democrats in both the House and Senate have supported the idea of balancing the budget by 1991, they oppose the particulars of the Senate proposal.

''It was horrible. The water came through and it took my father, my mother, my four brothers and my niece.''

Egyptian and American scientists are combining space-age technology and archeology to try to preserve an artifact potentially as precious as the rarest of Egypt's antiquities: a sample of 4,600-year-old air. Scientists interviewed here and in the United States said they believed the air was trapped in a burial chamber that was also likely to house a more tangible treasure: the missing second ''solar boat'' built in about 2,600 B.C. by the ancient Egyptians to transport the soul of the Pharaoh Cheops to heaven. The funerary boat would almost certainly be the sister of the boat that Egyptian archeologists discovered in 1954 12 feet away from the current site. The first solar boat - some experts say it was used to take the soul along the Sun God's path across the heavens - was found in an underground chamber 25 feet from the southern face of the Great Pyramid of Giza, on the outskirts of Cairo. The discovery of the first boat, a 130-foot-long wooden vessel in superb condition, caused a sensation among antiquities experts and has been widely regarded since then as one of the most important finds of modern Egyptology.

In an unusual move, the National Academy of Sciences announced today that some of the nation's most eminent scientists were in an irreconcilable conflict over proposals to alter the recommended levels of certain vitamins and minerals in the human diet. Dr. Frank Press, president of the Academy, said the organization would therefore be unable to issue a new set of recommended dietary allowances ''at this time.'' The report had been expected this summer. A confidential draft of the report, whose contents were disclosed last month, recommended reductions in the dietary allowances for various nutrients. Today's decision means, in effect, that Academy officials are not accepting those recommendations. Thus there is no scientific basis, for the time being, for cutting back the amounts and kinds of food provided in meals and Government food assistance programs designed to meet the recommended dietary allowances.

New York State's Chief Judge yesterday proposed new guidelines intended to curb favoritism, political influence and a longtime perception of such evils in the appointment of conservators and guardians by judges in the state. The Chief Judge, Sol Wachtler, said the plan would limit abuses, open the process to public scrutiny and encourage selection of the most qualified guardians and conservators to oversee the financial affairs of incapacitated people and to settle estates of those who have died. Judges would keep the power of appointment under the new guidelines, which would bar their relatives, limit large-fee appointments to one a year and require making public all of those chosen and their fees. ''The public must be assured that the selection process is not influenced by improper favoritism and that the fiduciaries appointed are well-qualified to meet their responsibilities,'' Judge Wachtler said in announcing his plan. Under present rules, appointments are made at the sole discretion of judges. Over the years, these rules have produced recurrent reports of excessive fees, nepotism and other improprieties. Last year, debate on the issue was renewed after John A. Zaccaro was removed as the conservator of an estate to avoid what a judge called an appearance of impropriety.