What was going on when I was born?

YONKERS THE Westchester County Fair, dormant since 1949, will be revived at the Yonkers Raceway this Friday, and its nine-day stand may bring back memories for many. ''It is with a great deal of enthusiasm that we are bringing the fair back to Westchester,'' said Timothy J. Rooney, president of the Yonkers Raceway. ''Parimutuel racing doesn't return here until next month. And so we opted for a fair to give visitors a chance to enjoy some of the old country carnival flavor of yesteryear.'' By bringing people into the area, he added, ''We hope it also will give the city of Yonkers and the county an economic boost.'' Among the attractions scheduled are exhibition harness-horse racing, industrial and agricultural displays, a livestock exhibit, fireworks, vaudeville and, on the final day, an antique car parade. Mr. Rooney said the colorful midway would be filled with carnival rides, games and concession stands, provided by the James E. Streat's Shows of Orlando, Fla., to appeal to the young at heart. Rounding it all out, on the last two days there will be automobile thrill shows in the afternoon and evening by Joey Chitwood's internationally known daredevil drivers.

The possibility of manufacturing new forms of life or genetically altering human beings, who are described in Christian and Jewish Scriptures as created ''in the image of God,'' is raising new problems for theologians attempting to assess the morality of modern bioethics. The rapid advances in genetic research, which has succeeded in fabricating living organisms by gene splicing, or artificially combining genes, mean that ''those who would play God will be tempted as never before,'' according to a statement issued by officials of the National Council of Churches, the United States Catholic Conference and the Synagogue Council of America. But, theologians interested in science and scientists versed in theology say that what constitutes ''playing God'' is as yet undefined. The scriptures and traditions of religious communities do not address such modern scientific techniques. Genetic engineering enables the scientist to create new life forms by altering existing species through rear@ranging the genes passed on from generation to generation. A relatively new science, it has expanded rapidly in the last six years and now has a number of industrial and medical applications. Sometime in the future inherited illnesses may be eliminated by replacing abnormal genes carrying the diseases, and tests are under way on genetically produced interferon, an antivirus agent for humans.

FOR PERFORMERS AND PRODUCERS By TONY SCHWARTZ During the past several months on Bravo, a new cable-television network, Leonard Bernstein conducted the American Symphony Orchestra in a tribute to Aaron Copland, a group of jazzmen celebrated Eubie Blake and the Indiana University Opera Theater performed the ''The Greek Passion.'' On ABC's Arts, a second cable network, the schedule last month included a ballet choreographed by George Balanchine, profiles of Jean Renoir, Edgar Degas and Henri Toulouse-Lautrec and the St. Louis Ragtime Band performing a selection of Scott Joplin songs. On CBS Cable, which will make its debut in October, the schedule includes the premiere of a dance choreographed by Twyla Tharp, a one-woman show featuring Jane Alexander and twelve hours devoted to a drama about the life of Giuseppe Verdi. It sounds like a video version of the Renaissance. Indeed, in the most optimistic scenarios for the future, this flowering of the arts will be just one part of cable TV's brave new world. New cable systems promise up to 100 channels, and already networks aimed at specific interests - movies, sports and news, for example - are springing up. But many more channels will have to be filled, and that raises the possibility of even more specialized networks - ones devoted to narrow interests such as tennis and knitting, or even networks that feature a single art form - modern dance or theater, for example.

STAMFORD PAST the white picket fence and under the American flag that flies from the porch at 955 Cove Road come the sick, the suffering and the questioning. They are veterans of the Vietnam War, but to them the battle is not over. An enemy more deadly, they say, than the one they faced in the jungles of Southeast Asia still stalks them. The small green house serves as the Connecticut office of Agent Orange Victims International, a nonprofit organization that seeks to inform Vietnam veterans that some of the health problems they or their children suffer from could have been caused by exposure to a herbicide called Agent Orange that was used in Vietnam and elsewhere between 1962 and 1970. The co-directors of the two-and-a-half-year-old Connecticut chapter are James A. Sparrow, a 34-year-old former Marine, and Roger Pappas, 47, who is not a veteran. The men, both divorced, share the rented house and run the chapter from their living room. The Connecticut chapter was the first branch office established by the organization, which is based in New York City.

CENSUS figures indicating that the Island's population has stabilized and the impact of this on companies that previously grew with the population have sparked a debate among Long Island planners over the strength of the Island's economy. Some say that the Island has entered a ''no-growth'' or mature period - a polite way of describing economic stagnation. Others counter, saying that different economic measurements indicate continuing strength. Those who support the ''maturity'' thesis see the Long Island Lighting Company's entry into the retail energy systems business as evidence that changes in the Island's economy have prompted a shift in the strategy of one of the Island's oldest businesses, whose growth has traditionally been tied to increases in residential electrical and gas hookups - a source that is closely tied to growth in housing.

The Reagan Administration has terminated , a 1979 White House Community Conservation Guidance Directive that introduced to the Federal level the concept of ''extraterritoriality'' to planning considerations for large new shopping centers . Under the directive, the chief elected official of a community could request the preparation of a community impact analysis by Federal agencies whose actions could lead to the creation of a large commercial development that might prove counterproductive to urban revitalization.

I N clusters, they were streaming out of the center court enclosure at the All England Lawn Tennis and Croquet Club, most of them glum, a few smiling. The ones who were smiling were usually Americans. ''What a way,'' one of them said, beaming, ''to celebrate July 4th.'' Their controversial colonist, John McEnroe, had won the ''gentlemen's singles'' at Wimbledon and melted the iceberg of Bjorn Borg's streak of 41 victories here after five previous championships. But in his Fourth of July celebration, John McEnroe did not set off any fireworks. To his credit, he transformed himself from the Ugly American into a Yankee Doodle Dandy of almost impeccable manners and almost impassive control.

Old wives to the contrary, silence is not golden. If it were, silence would be heavily traded on international markets, fetching $400 or $500 an antidecibel in London or Zurich. No investment portfolio would be complete without some. Speculators would get rich investing in silence mines. Silence would be hoarded and used as a hedge against inflation. Periodically, the United States Government would drop hints that it was considering going on the silence standard. On crowded Manhattan streets, chains of purest silence would be snatched from the necks of unwary pedestrians.

One of the 27 bids submitted for the second phase of housing at Battery Park City calls for the development of the 12 sites by a consortium of prominent architects. The architects were commissioned to work on this bid by Milstein Properties, an owner and developer of commercial, residential and hotel properties in Manhattan. The largest of four rental towers was allotted in the proposal to Philip Johnson and John Burgee. Another was assigned to Paul Rudolph and two to a joint venture of John Carl Warnecke and Peter Berman. Eight smaller buildings containing cooperative apartments would be designed by Marcel Breuer Associates, Conklin & Rossant, Eisenman Robertson Architects, Gwathmey Siegel Associates, Richard Meier & Partners, Mitchell Giurgola, Eliot Vilkas/Joseph Wills and Ada Karmi Melamede.

TRENTON ONE of the most far-reaching controversies in New Jersey legislative history - the role of the state in family life - is still being bitterly debated by educators, laymen and legislators. Last month, 10 months after the State Board of Education required all public schools in the state to provide family-life education from kindergarten through the 12th grade, an Assembly bill to kill that mandate fell only five votes short of the 41 needed to carry. The sponsor of the measure, Assemblywoman Marie S. Muhler, Republican of Freehold, says she will try again. The issues that nearly sent the mandate tumbling to the Assembly floor were home rule vs. state power, party politics and teacher insecurities. In addition to those opposing sex education on moral grounds, there are those who feel that the state board does not have the right to tell local school districts what kind of education to provide and those who feel that such mandates are the province of an elected body - the Legislature.

THE SAGE OF MONTICELLO Vol. VI, Jefferson and His Time. By Dumas Malone. Illustrated. 551 pp. Boston: Little, Brown & Co. $19.95. THE JEFFERSON SCANDALS A Rebuttal. By Virginius Dabney. Illustrated. 155 pp. New York: Dodd, Mead & Co. $8.95. NOTHING so much fascinated 19th-century Americans about the life of a hero as his leaving of it. Deathwatches and last words were the enduring stuff of legend. No American legends could have been better served by the drama of death than those of Thomas Jefferson and John Adams, the last of the great Revolutionary figures. On the 50th anniversary of the Declaration of Independence, within five hours of each other, both breathed their last, Jefferson first with the question, ''Is it the Fourth?'' Then Adams, saying, ''Thomas Jefferson still survives,'' which were destined to be his most famous words.

SCHOOL enrollment in the state continues to decline, more and more school officials find themselves wrestling with the problem of disposing of surplus buildings. In many districts, the first empty classrooms were considered a boon. They enabled educators to relieve crowding, offer a more diverse and enriched curriculum and provide space not only for daytime programs in adult education, but also for administrative offices, foreign-language laboratories, preschool programs, library centers and storage. However, when additional space is no longer needed, many districts find themselves with vacant schools that threaten to become a financial drain and community eyesore. For most districts, the first logical step was to rent, lease or sell the building to another governmental agency, and today some former schools are used for county and municipal services. However, when such arrangements run their course, as they have in a number of districts, school officials begin to look to the private sector for buyers.