What was going on when I was born?

The Reagan Administration warned Lebanese Shiite leaders today that if they failed to release 40 American hostages unconditionally, they would become international ''outcasts'' deprived of future American help. At the same time, the Administration reiterated that it would never yield to the demands of those who are holding the hostages. Opening a new Administration drive to persuade the Shiites who are negotiating for the hijackers that they had little support, even in the Arab world, Secretary of State George P. Shultz listed Algeria, Syria, Egypt, Iraq and Tunisia as Arab countries that had either condemned the hijacking publicly or had told the United States privately they would help to bring about the release of the American hostages.

FOR the professional horticulturist the hours are long, the work sometimes muddy and the pay not proportionately rewarding. Yet increasing numbers of young people are venturing onto the path that leads to gardening careers. Last year, for example, at the New York Botanical Garden, one of the institutions that offer a certified, professional-level program, there were 54 applicants for 20 places in the 19-month session, according to Dr. Arnold Gussin, an assistant vice president and director of education. ''We've seen progressively increasing numbers of applicants over the last few years,'' he said.

THURSDAY, JUNE 20, 1985 Companies Ted Turner defended the financial viability of his bid for CBS. In a filing to the F.C.C., he said that merging Turner Broadcasting System with a streamlined CBS broadcasting operation would jeopardize neither the competitive position nor financial status of the CBS network. According to investment banking sources, within the next month CBS may attempt to buy as much as one-third of its shares and require that anyone making a hostile takeover bid pay off immediately the debt incurred in the buyback. [Page D1.] A 1981 Hutton document addressed to its former president, George L. Ball, and other high officials reported that certain regional offices were making big profits through bank overdrafts. The document was among several a House subcommittee released to bolster its contention that top officers of the firm had knowledge of the scheme, to which Hutton has pleaded guilty. A spokesman said Mr. Ball did not recall such a document. [D1.]

An article yesterday on a rise in church membership in the United States incorrectly described the 219 denominations counted by the National Council of Churches. Roman Catholics were included in the total membership figure of 140,816,385.

Ted Turner, the Atlanta cable and broadcast entrepreneur, vigorously defended the financial viability of his bid to take over CBS, in a filing to the Federal Communications Commission made public yesterday. Mr. Turner's comments sharply contradicted arguments by CBS in its June 3 petition requesting the five commissioners to deny Mr. Turner's application to take over CBS's broadcasting licenses in connection with his $5.4 billion bid. Offering detailed financial projections for the first time, Mr. Turner said his plan to merge his company, Turner Broadcasting System Inc., with a streamlined CBS broadcasting operation would jeopardize neither the competitive position nor financial status of the CBS television network. Mr. Turner said that his plans to sell CBS's 18 radio stations, its two radio networks, one television station and the company's publishing division would increase the diversity of information available to the public. He contended that a merger would not diminish competition either in Atlanta, where he owns a television station, WTBS, or nationally.

Argentina's banks reopened today after three holidays, and its citizens stood in lines that snaked around entire downtown blocks, waiting to pay bills, ask questions, sort out accounts and withdraw money for expenses. Officials reported no bank runs, and no disorder. Instead, with some humor, some strong skepticism from unions, and a notable amount of cooperation, Argentines began to try on President Raul Alfonsin's new program that includes wage and price controls, a new currency - the austral - and some complicated conversions from Argentina's old pesos. The Alfonsin program is aimed at breaking the country's inflation rate of 1,010 percent, and reversing four decades of financial and social practices dictated by double- and triple-digit inflation.

An article yesterday on awards by the MacArthur Foundation incorrectly described a past position held by Morton Halperin, one of the award recipients. He was Deputy Assistant Secretary of Defense in the Johnson Administration.

The Transit Authority has failed to collect - and probably cannot recover - as much as $100 million from the city, state and Federal Governments, transit officials said yesterday. They said that because of the authority's haphazard methods of documenting expenses to which it was entitled, the authority would probably have to write off the loss over the next few months. ''In a lot of the cases, nobody ever put the pieces together,'' the executive vice president of the authority, George W. Miller, said. ''Nobody ever made up the bill, nobody ever sent the bill out.''

In an unusual display of bipartisan unity, the nation's mayors today urged Congress to amend President Reagan's tax plan to allow continued deduction of state and local taxes and to retain the tax-exempt status of municipal bonds. To make up that revenue loss, they asked that wealthy individuals and corporations be taxed at a higher rate than the maximum of 35 percent that the President proposed. The action came by near-unanimous voice vote on a resolution adopted at the close of the annual convention of the United States Conference of Mayors, composed of representatives of cities with populations of at least 30,000. Mayor John E. Mercer of Sunnyvale, Calif., a Republican whose city is a suburb of San Jose, cast the only ''no'' vote that could be heard.

By establishing as his ''primary goal'' the safe return of American hostages held in Lebanon, President Reagan has turned to a policy of restraint along the line followed by Jimmy Carter in the Iranian hostage crisis, foreign policy and Congressional officials said today. The parallels were being widely commented upon throughout official Washington today, for Mr. Reagan finds himself relying on an approach that he criticized as a Presidential candidate in 1980 and that he promised to change immediately upon being sworn into office in 1981. Setting aside that 1981 promise of ''swift and effective retribution'' against terrorists, the President enunciated what amounted to his new position publicly at a news conference Tuesday night. By saying he would follow this policy ''as long as the people are there and threatened and alive,'' Mr. Reagan was telling the national television audience what Administration officials have been saying privately since the hijacking of a Trans World Airlines plane Friday set off a foreign policy crisis for the President.

THURSDAY, JUNE 20, 1985 International The U.S. warned Lebanese Shiite leaders that if they failed to release 40 American hostages unconditionally, the Shiites would become international ''outcasts'' deprived of future American help. At the same time, the Administration reiterated that it would never yield to the demands for freeing the hostages, who are being held in Beirut. [Page 1, Column 6.] The pilot of the hijacked T.W.A. airliner issued a warning that any American rescue attempt would be futile. ''I think we'd all be dead men if they did because we are continuously surrounded by many, many guards,'' said Capt. John L. Testrake. [A1:5]

Marie and Robert Richardson grew up in Harlem, raised their two daughters in the Bronx and Chappaqua, N.Y., and, after their youngest, Kim, finished college last year, moved to an apartment in Guttenberg, N.J. Now they want to complete a circle by ''coming back home'' to Harlem, Mrs. Richardson said, and buying a brownstone that ''could be a legacy to our children.'' ''We're interested in the Mount Morris Park area,'' she said. ''I remember playing in the park as a kid.'' The Richardsons were among perhaps 1,000 people who gathered at City University's Great Hall the other day to hear city officials and real-estate experts explain how to participate in the auction of 149 city-owned brownstone, limestone and brick houses. The city's Department of Housing Preservation and Development will be accepting sealed bids on the houses until June 26.