What was going on when I was born?

President Reagan ordered an investigation today into why five American advisers in El Salvador apparently violated United States policy by carrying M-16 rifles in what may have been a combat zone. A videotape broadcast Thursday by the Cable News Network shows several men identified by the camera crew as Americans in civilian clothes carrying M-16 rifles and .45-caliber pistols. According t o the rules for United States advisers in El Salvador described in a State Department background paper last March, the advisers are allowed to carry only side arms, which they may use only in self- defense. An official at the United States Embassy in San Salvador confirmed that an adviser or advisers - he was unclear how many were involved - carried M-16 rifles ''in insecure territory.'' He said the Americans were not engaged in aggressive acts.

The United States Gold Commission recommended today that the Government mint a new gold ''coin'' that would be sold in competition with coins made by Canada, South Africa and other countries. The commission, in a 13-2 vote, proposed the creation of what the members in their discussion had dubbed ''The American Eagle,'' although it would not be used as legal tender, despite its designation as a coin. The Eagle would be similar to the Government's existing gold medallion, but would be exempt from capital gains and sales taxes. That might make it more popular as an investment vehicle than the current medallion, which has not sold well.

President Reagan, bowing to opposition from civil rights groups and several Democratic Senators, today withdrew his nomination of William M. Bell for the chairmanship of the Equal Employment Opportunity Commission. He announced his intention to nominate an Education Department official for the job. A White H ou se official said that Mr. Bell, owner and the sole employee of a Detroit job-recruiting concern, had asked that his name be withd rawn. Several members of the Senate Labor and Human Resources Com mittee had said he was unqualified and that they would oppose his co nfirmation.

President Reagan's proposed budget has drawn highly unusual public attacks from West European finance ministers, central bank chiefs and many private economists, who assert that the big projected deficits will further depress their own economies. President Reagan formally announced his budget last weekend, and since then Finance Minister Jacques Delors of France, Chancellor of the Exchequer Sir Geoffrey Howe of Britain, Finance Minister Willie de Clercq of Belgium and Karl Otto Pohl, president of the West German central bank, have all called it, in effect, a threat to the world's economic health. They have urged Mr. Reagan and Congress to reduce the $91.5 billion deficit projected for the fiscal year that begins Oct.1. Effects Already Being Fe lt Indeed, the complex economic mechanism by which a big United States budget deficit tends to raise interest rates and unemployment in Western Europe and throughout the world is already starting to operate: Since President Reagan made his budget proposals, American interest rates have gone up and the value of the dollar, in turn, has risen sharply against other major currencies as investors have transferred funds into dollar investments. Senior officials at the Organization for Economic Cooperation and Development, along with many private European bankers and economists, say another large United States deficit, coming on top of this year's expected $99 billion deficit, will keep interest rates high throughout the world.

A Rutgers University building whose occupants were found by the state to have an excessive number of cancers was closed Thursday night after air samples yielded increased levels of a hormone suspected of causing cancer. Earlier monitoring had found sharply lower readings. Dr. Edward J. Bloustein, president of Rutge rs, said he had ordered that classes in the building, Smith Hall, be suspended until further testing by the state and Federal governments determined its safety. The hormone, an estrogenic substance called estradiol benzoate, was found in the air of five of seven rooms tested last September by the Federal National Institute for Occupational Safety and Health. The substance is known to cause cancer in mice and is suspected of causing uterine cancer in women, a report from the institute to Rutgers said. Eight cases of cancer have been detected among those who regularly work at Smith Hall.

The United States and Morocco announced agreement today on a joint military commission and on steps that are exp ected to lead to transit rights f or American military forces. The two developments were disclosed by Secretary of State Alexander M. Haig Jr. at a news conference before he left for a brief visit to Rumania, where he is to meet President Nicolae Ceausescu on Saturday. 'A Strategic Consensus' The actions have the effect of bringing the two countries closer together militarily than at any time since two United States Air Force bases in Morocco were phased out in the 1950's and 1960's. Mr. Haig said that in his several hours of talks with King Hassan II, ''the main focus'' was on strategic matters. The Reagan Administration has given continuing emphasis to achieving what Mr. Haig has called ''a strategic consensus'' among the various nations in the region against what are perceived as Soviet and Soviet-backed threats.

Prime Minister Margaret Thatcher's chances of winning the next general election, which were considered almost nonexistent three months ago, appear to be improving. In a season of subtle but significant changes in the tenor of British politics, Mrs. Thatcher and her resolutely cautious policies no longer seem quite so embattled. This week a London bookmaker went so far as to install her Conservative Party as a narrow favorite to win the election, which is expected in the spring of 1984. The most important development has been a slowing of the momentum of the new Social Democratic Party, which burst upon the British political scene just a year ago with tremendous force, and which won its most notable victory late last year when Shirley Williams captured the previously Conservative seat at Crosby, near Liverpool, in a by-election.

A Government spokesman says that disclosures that followed a meeting of the British Medical Association's ethics committee might alter the views of medical groups advising the Government on the implications of research on ''test tube'' babies. The Government will be consulting medical experts in response to the ''great public concern'' over the subject of such research, said Michael J. Ricketts, spokesman for the Department of Health and Social Security, which will handle the investigation.

A martial law court today sentenced to prison three accomplices of Mehmet Ali Agca, the man who tried to assassinate Pope John Paul II, on convictions of hiding Mr. Agca after his escape from a Turkish prison in 1979. Officials said the three, Hasan Murat Pala, Mehmet Dursun and Mustafa Dikici, were each sentenced to three years and one month for hiding Mr. Agca and for helping him out of Turkey after his escape from a military prison in Istanbul on Nov. 25, 1979.

Secretary of State Alexander M. Haig Jr. arrived here tonight for talks on Saturday with President Nicolae Ceausescu in response to an urgent request for the meeting by the Rumanian leader. This is Mr. Haig's first visit as Secretary to a country that is a member of the Warsaw Pact, and it takes on pa rticular importance given the rising East-West tensions over the crackdown in Poland. Earlier this week, Mr. Haig led Western natio ns in attacking the Soviet Union and the Polish Government at a m eeting of the East-West conference in Madrid.

Greeted with exuberance by huge crowds in black Africa's most populous city, Pope John Paul II today began an eight-day journey to four West African nations. ''For me this is a moment of joy,'' the Pope said in responding to the airport greeting by President Shehu Shagari. ''Before me there unfolds a vision of hope.'' The 61-year-old John Paul stepped off the plane after a five-and-ahalf-hour flight from Rome, his first trip outside Italy since he was shot last May. The joy that he expressed seemed deeply felt on the first stop of the journey, which will also take him to Benin, Gabon and Equatorial Guinea before he returns to Rome next Friday.

A Manhattan State Supreme Court jury found Arnold Iannacone guilty of second-degree manslaughter yesterday in connection with the Oct. 19, 1980, murder of his brother-in-law, Anthony Fiore, a Citibank vice president.