What was going on when I was born?

Diana Rosado, a bright and determined 16-year-old student, was called to her school's guidance office to explain her uncharacteristic absences. ''My mother left me,'' she said, and broke down sobbing as she told how her mother, troubled by illness and alcoholism, had walked out on her and her three sisters during the summer. Helene Amarose, 16, used to be the kind of student teachers long for. Articulate and intelligent, encouraged by a family that valued education, Helene brought home good grades. But then Helene turned indifferent, even hostile about school, and missed three semesters. She is still at a loss to explain why. Accounts like these are often heard by guidance counselors and principals of the city's public high schools, where over a third of the students are chronically absent - missing classes more than 15 days out of each 90-day semester. Interviews with 60 students whose frequent absences have caused them to fall at least a year behind in school indicate that truancy is a widespread problem among students from strikingly different backgrounds.

An article in Business Day on Thursday incorrectly reported the number of shares outstanding of Home Depot Inc. of Atlanta.

From Piraeus to Hong Kong, from Baltimore to Liverpool, the world's major harbors are jammed with vessels built to transport American grain to the Soviet Union, Saudi oil to France, Japanese videotape recorders to Britain. But for more than a year, many of the tankers, bulk cargo vessels and container ships that make up the world's maritime industry have not sailed anywhere. And, if projections about world economic recovery are correct, their next port of call could well be a scrap yard in Taiwan. The industry is caught in a classic squeeze: Too many ships are chasing too few customers. As a consequence, freight rates and ship values have fallen sharply and the industry is mired in a recession that some analysts say could last through the mid-1980's. The downturn has created yet another potential trouble spot for international bankers, who are already besieged with problem loans.

Editorials in today's issue of the Journal of the American Medical Association urged the banning of boxing in light of new evidence suggesting that chronic brain damage was prevalent among fighters. In the same issue, the association's scientific council recommended that, if the sport is to continue, a number of measures be adopted to improve the monitoring of a boxer's condition before, during and after fights. One recommendation is that ringside physicians be empowered to stop a fight at any time. One editorial, written by Dr. George D. Lundberg, the journal's editor, said: ''No caring person could have observed the events in professional prizefighting in the past few months and not have been revolted. No prudent physician could have watched the most recent debacle/mismatch on Nov. 26, 1982, between Larry Holmes and Randall ''Tex'' Cobb and believe that the current boxing control system is functioning.''

''Why should a claim for a damaged leg survive one's death where a claim for a damaged name does not? After death, the leg cannot be healed, but the reputation can.

IT'S a nice idea: musical dynasties. When the National Orchestra of New York gives the first of four concerts Sunday in Carnegie Recital Hall, it will be one - as will be the three others - that will make some listeners think of the old heredity-versus-environment debate that still agitates researchers in psychology and related sciences. Three generations of Mozart will be on the matinee concert, conducted by Roger Nierenberg. Papa Leopold, of course, and his great son, Wolfgang, and Wolfgang's sweet, sad, ineffectual son, Franz Xavier. Then, on Feb. 20, Alvaro Cassuto will take a look at the two Scarlattis - Alessandro and Domenico. Domenico, who lives today primarily by his remarkable little sonatas, also composed in all forms, and three of his symphonies and a ''Salve Regina'' will be heard. Mr. Cassuto returns March 27 with music by the Bach family. That includes the mighty Johann Sebastian and three of his sons - Wilhelm Friedemann, Carl Philipp Emanuel and Johann Christian. Finally, on April 10, Ransom Wilson will conduct and play on the flute music by the brothers Haydn. Franz Joseph was, of course, the big Haydn, but his brother Michael was well known in his day and considered the peer of any European composer. All tickets are $6 and may be bought at the Carnegie Hall box office, 154 West 57th Street (information: 247-1228).

A 15th-century saint dedicated to meditating atop a pillar in the desert is subjected to temptations by a female devil in ''Simon of the Desert,'' by the master of surrealist film, Luis Bunuel. The 1965 feature will be shown today at Film Forum 2, 57 Watts Street, at the start of a Bunuel retrospective that runs through Feb. 1. Another feature, ''Viridiana'' (1961), about corruption in the Roman Catholic Church, will also be shown today, along with a short, ''L'Age d'Or (1930), one of the director's experimental films with Salvador Dali. The site is two blocks north of Canal Street at the Avenue of the Americas. Admission: $4.50. Information: 431-1590. THE GOALIE OF 90TH ST. The British actor Jim Piddock, who appeared recently with George C. Scott in ''Present Laughter'' at Circle in the Square, stars in a one-man play having a limited run at the York Theater, 2 East 90th Street. The play, ''The Boy's Own Story,'' by Peter Flannery, playwright in residence at the Royal Shakespeare Company, is described as a biting comedy. In it, a soccer goalkeeper who hates the game speaks about his feelings and fantasies while making spectacular saves in the face of flying soccer balls. Tickets are $8. Reservations: 534-5366.

THERE is something that the Metropolitan Museum of Art shares with the New York Yacht Club, the Dutch Reformed Church on Flatbush Avenue in Brooklyn, St. David's School on East 89th Street, the Appellate Division Courthouse on Madison Avenue at 25th Street, the headquarters of the Columbia School of Journalism, the Players Club on Gramercy Park South, the United Nations Secretariat building, the Cathedral of St. John the Divine, Tavern on the Green and Maxwell's Plum. What they have in common is that they all have something to contribute to the history of stained glass as it can be studied in New York City. The Metropolitan Museum and the Cloisters, its auxiliary in Fort Tryon Park, are of course, primarily concerned with stained glass as it was practiced in Europe in the Middle Ages. But New York City has its own history, where stained glass is concerned, and that history is long, rich, complicated and occasionally hilarious.

An article in Metropolitan Report Dec. 14 about a freeze on hospital construction in New York State listed one hospital too many. Montefiore Hospital and Medical Center had already received approval for its construction plans and was not affected.

The police attacked a house with rifles and tear gas today, killing seven black members of a religious cult who had held an officer hostage for 30 hours while beating him to death. The authorities said the officer, Patrolman R.S. Hester, 34 years old, apparently died several hours before the police decided to try to rescue him. His body, with his hands manacled behind his back, was found just inside the front door. The delay in raiding the house was denounced by several officers. One officer, who said Patrolman Hester's screams were heard half a block away when the standoff began Tuesday night, asserted that police commanders ''let him die - that's just the bottom line.''

The Associated Merchandising Corporation and Frederick Atkins Inc., the country's largest store-owned buying offices, have taken the first step toward a possible merger. Lee Abraham, chairman of Associated Mechandising, yesterday confirmed retail trade reports that the principals of the two offices have discussed merging. But, he added, ''The talks were very preliminary and basically exploratory concerning the possibility of combining the two organizations.''

The first Battle of Poitiers, in which a Frank warlord known as Charles (The Hammer) Martel saved Christendom by crushing an advancing Moorish army in A.D. 732, is widely recognized as a turning point in world history. Now, the French Government of President Francois Mitterrand is fighting another Battle of Poitiers, but this time the objective is to save the French video recorder market from being overrun by Japanese imports. Since last November, all foreign-made video recorders entering France must be cleared through a nine-man customs depot in this pleasant town in western France -which, not coincidentally, is hundreds of miles from the northern ports where the units are landed. Once the recorders make their way to the depot here, they are subjected to intensive, time-consuming checks. And by coincidence, 732 is the code number the French Customs use to identify goods coming from Janpan.