What was going on when I was born?

The Whittaker Corporation, a diversified manufacturing company, announced yesterday a $668 million tender offer for the Brunswick Corporation, a major producer of recreational products. Whittaker, which is based in Los Angeles, said that it would pay $320 million in cash for Brunswick stock and debentures in the first phase of its proposed acquisition. The manufacturer said that the second phase would involve an exchange of Whittaker stock for Brunswick. Whittaker valued the second phase at $348 million.

An explosion shattered a basement classroom at Camden County College's Urban Center today, injuring 50 students and faculty members. Two of those injured were reported in critical condition with head wounds and two were listed in serious condition. The condition. The rest were released after being treated at hospitals in Camden.

Gen. Wojciech Jaruzelski today attacked the economic sanctions imposed by the United States, insisted that martial law was justified to avoid civil war and called for ''sacrifice and labor'' from the people to lead Poland out of its crisis. In a speech to Parliament, General Jaruzelski, who is Prime Minister, Communist Party leader and head of the rul- Excerpts from speech, page A8. ing Military Council, set no date for lifting martial law. He said he wanted to end it ''as soon as possible'' but it depended on conditions in the country. If all remains quiet, he said, some restrictions could be eased or lifted by the end of next month. He then added: ''Poland is exhausted. Poland has been exposed to danger. The antisocialist forces and foreign broadcasts excite actions of terrorism. Let there be no mistake. The only result of such actions would be a lengthening and sharpening of the state of war.''

''Man cannot live by cheese alone.'' - The Rev. J. C. Crawford, of Newark. (B3:6.)

NEARLY a decade after American psychiatry deleted homosexuality from its list of mental illnesses, the profession remains polarized in its views, to judge by the vigorous debate at a major symposium on homosexuality last weekend. Some professionals, primarily classical psychoanalysts, insist that homosexuality is inherently abnormal; others more sociologically oriented maintain it is a normal variant of human sexual behavior. Some say dissatisfied homosexuals should be offered therapy to help them become heterosexuals; others, especially homosexual psychiatrists, say unhappy homosexuals should be helped only to become happier with their sexual orientation. Whatever their views, nearly all denounced homophobia (fear and hatred of homosexuality) and prejudice, which they said pervades the psychiatric profession as well as society at large. Dr. Judd Marmor, a Los Angeles psychiatrist who is a professor emeritus at the University of Southern California, asserted that homosexual physicians were still denied res idency training in psychiatry by mosthospitals and that no psychoanalytic institute would knowingly accepta homosexual trainee.

and perhaps even caused by - gradual failure of the immunological defense system that fights invasion from the outside and subversion from within. Research on the immune defenses' decline with age has focused new attention on a pinkish-gray two-lobed organ called the thymus gland. Mysteriously, the thymus begins its own decline when many organs are still growing. Does that early decline lead the way in an inexorable chain of events that weakens the defenses of the aging human body? Is it a key event in aging itself? And, if so, might replacement of some of the gland's products slow the process? The gland, located high in the chest, is an essential component of the immune system, but it reaches greatest size at sexual maturity, about the age of 14, and begins to lose bulk and diminish in function long before the body's overall immunological processes become noticeably weakened.

A bill that would raise minimum taxes for corporations and individuals, bringing in $8 billion a year in Federal revenues, is being drafted by Senator Robert Dole, according to his aides. He is said to want to meet criticism that the 1981 tax law favored the wealthy as well as to help reduce budget deficits. The Reagan Administration would apparently not oppose higher corporate minimums. (Page D1.) New orders for manufacturers' durable goods rose 1.6 percent in December, their second moderate gain after a 9.8 percent drop in October, the Commerce Department reported. An official saw the increase as a sign that the recession was ending, but private economists were doubtful. New orders for all of 1981 rose 7.3 percent, or virtually not at all after allowing for inflation. (D1.)

An article about the Rangers-Capi- tals hockey game in some copies of SportsMonday yesterday gave an in- correct career statistic for Dennis Maruk of the Capitals. He has 500 points - his total of goals and assists.

International Martial law in Poland was defended by Gen. Wojciech Jaruzelski, the country's leader, in a speech to Parliament. General Jaruzelski did not say when martial law would be lifted, but said he wanted it to end ''as soon as possible.'' He reiterated that martial law was necessary to avoid civil war, attacked the United States economic sanctions and urged Poles to pull tee country out of its crisis. He was vague about what role, if any, the suspended Solidarity trade union would play in the future. (Page A1, Column 1.) Poland will not be discussed by Foreign Minister Andrei A. Gromyko of the Soviet Union when he confers today in Geneva with Secretary of State Alexander M. Haig Jr., who has said that his purpose in his talks with Mr. Gromyko is to express directly the West's ''outrage'' over Poland. Mr. Gromyko said he had ''no intention whatsoever'' to discuss the Polish situation. Mr. Haig responded: ''Well, I think it could be a very short meeting then.'' (A6:1-6.)

El Salvador's political and military leaders call them ''terrorists'' and blame Communist subversion for the war here. United States officials agree with what those leaders say: that Cuba and Nicaragua are supplying weapons, training and men. But the peasants and their leaders here in the province of Morazan, where the anti-Government movement is the strongest, contend that theirs is an indigenous revolution spawned by decades of political and social injustice. The revolution, they say, is being fought primarily by peasants who were born and raised in the areas where they are fighting. For two weeks, this reporter walked and lived with the guerrillas in the northern part of Morazan, roughly an area stretching from midway between Perquin and San Francisco Gotera to the Honduran border, in an attempt to get answers to some of the questions about the movement.

President Reagan has rejected the nearly unanimous advice of his top advisers and decided not to propose increased excise taxes in his State of the Union Message Tuesday night, Administration officials said today. The officials said that Mr. Reagan had changed his mind over the weekend and reversed a decision he reluctantly made last week to propose roughly $45 $45 billion in higher taxes on liquor, and gasoline in the fiscal years 1983 and 1984. However, Mr. Reagan was reported to have decided to resubmit a package of some business tax increases designed to close certain ''loopholes,'' raise fees and repeal certain ''unfair'' tax credits. These taxes were understood to involve less than $30 billion spread out over 1983 and 1984.

Mayor Koch, freshly returned from an eight-day vacation in Spain, suggested yesterday for the first time that he might consider seeking the Democratic nomination for Governor. Mr. Koch did not say yes, he was running. But he was careful not to say no as firmly as he had dozens of times before, when he flatly ruled out a race for any office other than Mayor and talked about life in Albany as ''a fate worse than death.''