What was going on when I was born?

IF a group of physicians who call themselves clinical ecologists are right - there are those in the medical profession who do not believe that they are - thousands, perhaps millions, of Americans are ''allergic'' to the world they live in: to common foods such as wheat, milk, corn and eggs; to food additives and pesticides; to chemical pollutants in the air and water. The symptoms of their sensitivities are said to include such behavioral and emotional problems as depression, fatigue, irritability and even schizophrenia, as well as such physical ones as headaches, stuffy sinuses, nausea and diarrhea. Some of these people have put in weeks in isolation in hospitals and spent thousands of dollars on diagnostic tests only to be told that they are reacting adversely to myriad substances encountered in the course of daily living. Many others have returned dozens of times to the doctor's office for costly, time-consuming treatment to curb their presumed food and chemical sensitivities. Some live on highly restrictive diets in hopes of avoiding the foods thought to trigger their symptoms. Others have paid large sums to ''detoxify'' their homes by replacing all gas cooking and heating units with electric ones, buying hypoallergenic carpets and bedding, and banishing all sprays and scents. Not a few have abandoned ''contaminated'' urban and suburban dwellings and moved to a relatively unpolluted mountaintop or seashore.

Jan. 1, 1985, was Peter Powers's first day back on the track, Simone Garvey's first day without coffee and Juliana Harkavay's first day. It was gray and overcast, and as a gentle mist whispered through the city, Mr. Powers was in Central Park running, Miss Garvey was at a diner drinking orange juice, and Miss Harkavay was squinting at the light that filtered through the window at St. Luke's Hospital, where she was the hospital's first baby delivered in 1985. Yesterday was a day tinged with firsts, when anyone could find something to begin anew - a diet neglected during holiday parties, an exercise program abandoned when the summer sun set, a book that seemed too long, a friendship that was somehow forgotten. For Berta Carela-Harkavay and Michael Harkavay, the new year began with a burst of crying at 1:27 A.M., when an 8-pound, 2-ounce little person with a shock of black hair entered their world.

''CUCINA GENUINA'' is not a new phrase in Italy, but it has been gaining fresh currency lately. Cucina genuina means cooking that is genuine, in the sense of authentic, unadulterated and natural. It also means cooking that is closely tied to the traditions of a particular region. In Italy that meaning is as manifold as the 19 separate regions into which the country is divided. Many dishes in the regional Italian cook's repertory now appear nationwide, whether on restaurant menus or in home kitchens, from Turin to Palermo - dishes like spaghetti bolognese or pasta alla carbonara. But Italians are the first to point out there is really no such thing as Italian cooking. When Italians talk about food - which they do constantly, unabashedly and with gusto - they talk about regional food, the cooking of Piemonte in the northwest or of the Abruzzi hill country east of Rome, or the rich, Arab-influenced cuisine of the south. Even within regions such as Tuscany, there are discernible and cherished differences among the cooking styles of Florence, Siena, Lucca and Arezzo. After a brief fling with nouvelle cuisine, which often seemed a press agent's airy fantasy rather than a response to actual needs,

WEDNESDAY, JANUARY 2, 1985 International China's new ''open door'' policy to the West is the only way to overcome the legacy of ''poverty, backwardness and ignorance'' the country brought on itself by hundreds of years of isolation, according to Deng Xiaoping. China's pre-eminent leader made the statement to his fellow Communist Party leaders in a speech made public in Peking. (Page A1, Column 4.) The new arms control talks scheduled next week in Geneva have raised hopes among many Russians for improved relations with the United States. However, Soviet officials seem to be approaching the ministerial talks cautiously. (A10:1-4.)

Two years ago, a group of Boy Scouts walking along the beach in the State of Washington spotted a red-and- white sphere bobbing in the water. On its sides, written in Russian and English, was the phrase ''USSR Academy of Sciences,'' suggesting that it was an innocuous research buoy. But when military investigators examined the sphere's innards, they concluded that it had a more sinister purpose. It was actually a military sonobuoy that had been dropped offshore, the investigators say, to eavesdrop on Trident missile submarines based in nearby Bremerton. Moreover, the acoustic buoy appeared to have been copied from American designs and electronic components. It even contained an extraneous screw, threaded the wrong way, that served no purpose whatever but was identical to the extraneous screws an American designer had used as a ''signature.''

WEDNESDAY, JANUARY 2, 1985 The Economy The Treasury's tax plan is having a chilling effect on some real estate investments. Investors, developers and prospective buyers of vacation homes worry that if the plan is approved, the loss of tax breaks will depress property values. (Page A1.)

The economy will be somewhat less vigorous, but most industries will expand output and earn higher profits in 1985, the Commerce Department said Monday in an annual report on the industrial outlook. The nation's economic growth will slow to about 4.3 percent in 1985, from 6.7 percent in 1984, but 85 percent of 209 manufacturing industries studied should be profitable, the department said. Most industries will grow somewhat less than in 1984, the department said, but higher military spending should mean a banner year for aerospace manufacturers, and primary metal producers may also do better than in 1984.

The Sahara has been extending its desert barrenness southward at the rate of 6 to 12 miles a year for more than a decade, gradually incorporating the Sahel, the semiarid belt at its southern fringe. But in 1984, in the worst drought that has been recorded across Africa from Mauritania to Djibouti, all of the Sahel has become Sahara, at least until the next rainy season. ''It is as if the desert advanced 125 miles this year,'' said Kit Macy, a representative of the United Nations World Food Program in Mongo, a bone- dry, sandy administrative center in the middle of Chad. The effect, in one of the poorest, least productive and least developed countries, has been catastrophic.

An Eastern Airlines flight from Asuncion, Paraguay, to La Paz, Bolivia, with 33 people aboard was more than five hours overdue, and a ground search was launched for the missing jet, airline officials said early today. Eastern Flight 980, a Boeing 727 carrying 25 passengers and a crew of 8, left Asuncion at 5:57 P.M. Tuesday and was reported overdue at 7:48 P.M., when it was scheduled to land in La Paz, said Richard McGraw, a senior vice president for the airline.

The Scouting column in Sports Pages yesterday misstated the date that the boxer Tony Ayala Jr. was arrested. It was New Year's Day 1983.

Before cutting taxes, New York State should start to pay off a short-term debt that has grown to more than $4 billion, the Citizens Budget Commission said yesterday. Otherwise, the civic group warned, the state could suffer the sort of fiscal crisis that crippled the New York City government 10 years ago. ''Should the state lose access to the short-term credit markets, which the New York City experience in the mid- 1970's established as possible, the consequences would be calamitous,'' the report said. 'A Public Policy Choice' To state taxpayers, who have heard talk of tax cuts for months, and to state politicians, who have looked forward to voting for such popular measures, this was the first significant negative voice.

''No country can now develop by closing its door. We suffered from this and our forefathers suffered from this.