What was going on when I was born?

A court-appointed panel has approved a plan to sell the Mortgage Guaranty Insurance Corporation to the Northwestern Mutual Life Insurance Company and an MGIC management group, the panel's chairman has announced. Proceeds from the sale of the mortgage corporation, a subsidiary of the troubled Baldwin-United Corporation, could be partly distributed to holders of Baldwin annuities. Baldwin-United filed for protection from its creditors under Federal bankruptcy laws in September 1983, and has been seeking to reorganize.

Walter F. Mondale plans to announce a plan Monday to reduce the Federal budget deficit by an estimated $175 billion in 1989, campaign aides said today. The Democratic nominee's plan calls for interim deficit reductions with the start of a Mondale Presidency next year, they said, reaching $175 billion, or two-thirds of the deficit's projected amount, at the end of the term in 1989. About half the $175 billion reduction would be achieved through cuts in domestic and military programs and the other half through a tax increase, the aides said. Based on January Proposals Meanwhile, Congressional Democrats said they feared Mr. Mondale's showing against President Reagan might hurt their campaigns. (Page B8.)

In a few weeks, Galway Irish Crystal will attempt to cash in on a new baby boom by selling its first infant- related item, a four-ounce, lead crystal baby bottle with a silverplated cap for about $38.50. The Boston-based distributor said there have been more than 5,000 requests for the bottle in the last two weeks. Lewis of London offers a $1,500 gold-plated crib at its New York store. ''Business is terrific,'' said Mindy Isacoff, the store manager. ''It's baby boom No. 2.''

MONDAY, SEPTEMBER 10, 1984 International The U.S. was ready to discuss a joint moratorium on tests of new space weapons with the Soviet Union, Secretary of State George P. Shultz said, but he ruled out a Soviet proposal for a freeze of such tests in advance of actual negotiations. Previously, the Reagan Administration had said it was willing to engage in talks with Moscow on curbing the militarization of outer space so long as there were no conditions. The United States had not specifically addressed itself publicly to the moratorium question. (Page A1, Column 4.) Jamaica is a heavy contributor to the worsening American drug problem despite its position as one of the closest political allies of the United States. In the face of Congressional threats to cut off millions in economic aid, Jamaica has steadily been producing large amounts of marijuana for export to the United States. It is also increasingly being used as a base for transshipping cocaine from South America, United States officials say. (A1:2.)

It was Nicole Anthony's day to be dipped in the water, to have her sins washed away and her spirit purified. It was her day to be baptized at the Upper Room Baptist Church. As the sun moved toward the horizon on a recent Friday, the 9-year-old contemplated the evening's coming event, when she would be admitted into Christianity and the church. ''I guess it's the same as getting a needle,'' she said, biting her nails. ''I'm scared about getting under the water.''

Nearly 20 months ago, Casey Powell led a much-publicized exodus from the Intel Corporation, taking with him 16 of the computer company's executives and engineers. At the time, Mr. Powell, then Intel's manager of microprocessor operations, said that the group had no clear notion of what it would make. But now, Sequent Computer Systems, the company they founded, has introducing its first product: the Balance 8000, a powerful multiprocessor that can be used in computer-aided design, image processing, automated testing and other engineering tasks. If all goes well, production models of the computer should be rolling off the assembly line by winter.

Among the 5,000 residents of rural Dawson County, Sheriff John David Davis was the law. The fact that he had once served time in the Federal penitentiary for moonshining and the gossip that he was the target of a Federal drug investigation did not seem to bother most people. Now, less than a month after he handily won re-election to a third term, Sheriff Davis, 51 years old, is in jail. He is being held in $3 million bail after Federal agents arrested him in Florida on Aug. 30 and charged him with conspiring with five others to import and distribute marijuana, cocaine and methaqualone. Sheriff Davis, who has pleaded not guilty, is one of 21 current or former sheriffs in Georgia and Tennessee to have been indicted in three years on charges ranging from narcotics trafficking to tax evasion. So far, 13 have been convicted and sentenced to jail. One has been acquitted.

''Why should everything be public?'' Rosalie Clifford said as she entertained neighbors on the back deck of her asphalt-sided, five-room house in the oceanside Queens community of Breezy Point the other day. ''Everyone's entitled to privacy. ''We don't want any outsiders coming in.'' If there is one quality that links the residents of Breezy Point, it is their passion for privacy. ''If you want public, you go over the bridge,'' said a neighbor, Betty Glennon, referring to the Gil Hodges Memorial Bridge, which must be crossed to get there. When people say Breezy Point, they usually mean Breezy Point, Rockaway Point and Roxbury, the three communities south of the Rockaway Inlet that make up the Breezy Point Cooperative and its 2,800 one-family houses. The cooperative owns 500 acres of land; residents own homes on the property and have shares in the cooperative, which was established in 1961. The entrance to the cooperative is guarded by a security checkpoint, and its privately owned streets are blocked to unauthorized traffic by electronically locked gates.

John McEnroe used his battery of serves and volleys, alternately overpowering and teasing, and dominated Ivan Lendl yesterday to regain the United States Open tennis title he held from 1979 to 1981. His 6-3, 6-4, 6-1 victory was a testimony to McEnroe's artistry and will, because it came less than 15 hours after his bruising five- set semifinal victory over Jimmy Connors, a match that lasted 3 hours 45 minutes and ended at 11:13 P.M. Saturday. ''I feel unbelievable and terrible at the same time,'' McEnroe said after winning his second consecutive Grand Slam tournament, running his match record for the year to 66-2 and collecting the $160,000 first prize. ''My body said, 'That's enough,' but the fact that I was tired made me concentrate better. The more tired I felt, the better I thought I hit the ball. It was a mental thing - push, push - and I didn't get angry at anything because I needed every ounce of energy I had.'' Conservation of energy was a lesson McEnroe had learned at the French Open, when the temperamental explosions that have marked his career turned a two-set lead into a five-set loss to Lendl, giving the Czechoslovak his first victory in a Slam event. After that defeat and another stormy display at a Wimbledon preparatory tournament, McEnroe has displayed a sort of serenity. ''I learned certain things about wasting energy,'' said the New Yorker who had gained the Wimbledon title with good manners and dazzling play, including a final-round trouncing of Connors that McEnroe characterized as his finest match ever.

Companies Bank deregulation faces increasing opposition in both houses of Congress as crucial tests loom this week. In the Senate, the bill is given only a 50-50 chance. And in the House, a different bill is threatened by an intense lobbying campaign led by Sears. (Page D1.)

Secretary of State George P. Shultz said today that the United States was ready to discuss a joint moratorium on tests of new space weapons with the Soviet Union, but he ruled out a Soviet proposal for a freeze of such tests in advance of actual negotiations. Previously, the Reagan Administration said it was willing to engage in talks with the Russians on curbing the militarization of outer space so long as there were no conditions. The United States had not specifically addressed itself publicly to the moratorium question. Mr. Shultz's remarks were apparently meant to convey an American readiness to discuss everything at the table, including a moratorium on future testing, but not to accept any Russian condition - in this case, a ban on tests while negotiations were taking place. The United States is expected to test an antisatellite weapon this fall.

New rules issued by the Federal Government sharply reduce the number of counties that must provide bilingual ballots to Hispanic-Americans and other minority groups in the election this November. Congress has authorized such ballots to protect the voting rights of citizens who cannot speak or understand English well enough to participate in elections. From 1976 through this June, 384 counties and other political subdivisions were required to provide bilingual election materials. The Census Bureau has calculated that 197 counties must do so under the new formula.