What was going on when I was born?

SOME 200 years ago, Mozart, writing to his father, referred to the pipe organ as ''the king of instruments,'' and the characterization has clung ever since to this biggest, most complex, most expensive and, for some, the most mystifying of musical instruments. Through the centuries, these ''kings'' have been been created, used and preserved mostly by churches, and opportunities to hear a fascinating variety of them abound in New York churches every weekend. But this weekend, as happens occasionally, another opportunity is available. Tomorrow night, there will be an organ recital at Alice Tully Hall, one of the city's two concert halls that have pipe organs (the other is the Metropolitan Museum's Rogers Auditorium). The recital on the Theodore Kuhn instrument in Tully Hall will be played by Fred Lallerstedt. The program will offer Mozart's Fantasy in F minor, Mendelssohn's Sonata No. 4, Franck's ''Grande Pi ece Symphonique,'' Haydn's Organ Concerto in C (with a chamber ensemble) and David Loeb's ''La Passacaglia Nuova.''

An important link between a cancer gene and a natural substance that promotes cell growth within the body has been discovered by a team of scientists in Israel, Britain and the United States. The discovery was reported yesterday in the scientific journal Nature, which commented in an editorial that ''the result is as dramatic as it will be important'' for research on cancer and on the processes of normal cell growth. The editorial said the work represented ''another leap forward in understanding the basis of cancer.'' Scientists in this country, familiar with the research but not directly involved in it, agreed with that assessment.

American naval gunners fired on Druse and Syrian artillery positions in Lebanon for a second day in retaliation for the shelling of mostly Christian East Beirut. An American Marine spokesman said a destroyer fired about 150 rounds from its five-inch guns. (Page A1, Column 6.) Americans will not be evacuated from Lebanon at this time because of concern that such a move would send the wrong political signal, according to authorities close to the United States Embassy in Beirut. They said an evacuation would upset negotiations aimed at keeping President Amin Gemayel in power. (A10:1-4.)

United States naval gunners bombarded anti- Government artillery batteries in Lebanon today for the second day in retaliation for the shelling of Christian- dominated East Beirut. The destroyer Moosbrugger fired ''roughly 150 rounds from its five-inch guns at artillery positions in the hills east of the capital'' at about 7 P.M., according to Maj. Dennis Brooks, spokesman of the Marine contingent at the airport. On Wednesday, the battleship New Jersey and the destroyer Caron reportedly firing more than 550 rounds toward Syrian-controlled areas. (The Damascus radio said Syria might be ''compelled to react'' unless the naval fire stops. The statement was broadcast as Syrian leaders met with Lebanese opposition leaders in Damascus. Page A10.)

Paul A. Volcker, chairman of the Federal Reserve Board, said today that he thought the financial markets had overreacted to statements by him and Administration officials that Federal budget deficits could sow another recession. ''I think that's a little blown up,'' he told Congressmen who asked him about Wednesday's 24.19-point decline in the Dow Jones industrial average. ''I think basically the outlook is bright.'' In today's trading, the stock average fell 3.56 more points. (Page D1.)

Representative Jim Wright, the House majority leader, said today that the Reagan Administration would have to agree to reductions in military spending before the Democrats would discuss other spending reductions and tax increases. Mr. Wright, a Democrat from Texas, outlined his position in a letter to James A. Baker 3d, President Reagan's chief of staff. His letter came a day after the first meeting of negotiators from the White House and Congress on Mr. Reagan's call for a three- year, $100 billion ''down payment'' on deficit reduction. The Wright letter is a toughening of the Democrats' position on the negotiations, which they have been skeptical about from the beginning. One reason is the worry about being politically trapped by the President into a quick settlement that could neutralize the deficit issue in the campaign. Another is confusion over the exact nature of Mr. Reagan's $100 billion offer, which was made in his State of the Union Message last month, and how far the Administration really wants to go this year in cutting the deficit.

''CHECK IT OUT!'' the local entrepreneurs used to shout when the attractions on the 400 block of West 42d Street included massage parlors and burlesque shows. There is still plenty of reason to check out the block between Ninth and 10th Avenues, but the lures today are of a very different sort. On what has been christened Theater Row, one can find nine plays this weekend, from a Restoration comedy to a socially conscious musical, from Wendy Wasserstein's look at the Zabar's crowd to Sam Shepard's meditations on the new West and two productions of Samuel Beckett. And although Playwrights Horizons began the rehabilitation of the block with its arrival almost a decade ago, Theater Row is still being discovered by uptown and suburban audiences. ''The most exciting thing,'' said Jack Garfein, artistic director of the Actors and Directors Theater, ''was the night I saw five limousines out front of the Beckett plays. I said to myself, 'We finally got the carriage trade.' ''

At 12 minutes 23 seconds of the opening period tonight, after Czechoslovakia had scored a goal against the United States Olympic hockey team despite being a man short, the lights went out at the Zetra ice arena. It was a dour omen for the Americans, who were defeated, 4-1, and practically eliminated from medal contention in the XIV Olympic Winter Games. The defeat came two days after a 4-2 loss to Canada by the United States, which was undefeated and won the gold medal at Lake Placid, N.Y., in the 1980 Olympics. With an 0-2 record now, there is little chance of a gold medal this time.

T. S. Eliot called it ''a titanic show,'' but Edmund Wilson found it ''revolting.'' The work is ''Epicoene, or the Silent Woman,'' Ben Jonson's 1609 comedy about the tormenting of a man who hates noise, and it begins a rare run tonight at 8 at the Cocteau Repertory, 330 Bowery. The director, Gerald Chapman, formerly resident director of London's Royal Court Theater, has set the play in New York, with farcical scenes inspired by the Marx Brothers. It runs two and a half hours. Tickets: $8.50. Reservations: 677-0060. SECOND AVENUE POWWOW The Thunderbird American Indian Dancers' midwinter dance concert and ''powwow'' - an Algonquin word for a coming together - starts tonight at the Theater for the New City, 162 Second Avenue, at 10th Street. They will perform, for instance, a Pueblo thunder dance in which hand motions express rain and the planting of corn, and an Apache rite in which masked ''spirits'' bless a maiden. Corn soup and fried breads available. Fridays and Saturdays at 8, Sundays at 3 and 5, this weekend and next. Admission: $4 (50 cents for under-12's accompanied by an adult Sundays). Reservations: 254-1109. VISIT TO THURBER'S WORLD

''We are deeply concerned about the amount of shelling. We are wondering whether or not our policy is dramatically changing.

The continuing success of low-calorie and so-called gourmet frozen foods has revived a market whose palate was dulled by traditional TV dinners. And this year promises an even broader range of entries as the nation's leading frozen food marketers fight for a bigger chunk of what is now the industry's fastest-growing and most profitable sector. The industry calls them ''premium frozen meals.'' And so far, analysts say, the three leaders are the Stouffer Corporation's Lean Cuisine, Swanson Foods' Le Menu and Armour Food's Dinner Classics. Weight Watchers' entrees and the Banquet Foods Corporation's Light and Elegant are a somewhat distant fourth and fifth.

The two top officers of the Drysdale Government Securities Corporation, which collapsed in 1982, pleaded guilty yesterday to defrauding the Chase Manhattan Bank of $270 million. The officers - Joseph V. Ossorio, chairman of the defunct Drysdale Securities Corporation and a director of the Drysdale Government affiliate, and David J. Heuwetter, who owned all of Drysdale Government Security's stock and was its chief trader - made their pleas in State Supreme Court in Manhattan. The two had been indicted on the charges last July and originally pleaded not guilty. Mr. Ossorio also admitted defrauding the Manufacturers Hanover Trust Company of more than $20 million. He could face an 18-year prison sentence, while Mr. Heuwetter could receive a maximum of seven years.