What was going on when I was born?

The 42-member Islamic Conference decided tonight to readmit Egypt, whose membership was suspended after it signed a peace treaty with Israel in 1979. ''The conference invites Islamic Egypt to resume its membership in the Islamic Conference Organization,'' a brief passage in the final document said. There was no mention of any conditions. The decision, reached at the end of a four-day meeting, followed an announcement from Cairo, after President Hosni Mubarak had met with his advisers, that the Egyptian Government would accept no conditions for its return.

FRIDAY, JANUARY 20, 1984 The Economy The F.C.C. voted to delay until 1985 imposing access charges on telephone users for links to long-distance networks. The commission cited pressure from the public and Congress. As a result, A.T.& T. will probably cancel much or all of the rate cuts of 10 percent to 15 percent that it had planned on long-distance services. The agency's decision was praised by the White House. (Page A1.) It was a partial victory for the host of A.T.& T.'s smaller competitors seeking a share of the long-distance market. (D4.)

An article in Business Day on Saturday about the Intel Corporation incorrectly described a payment by the Zitel Corporation. It was to retire warrants for Zitel stock held by Intel.

The BankAmerica Corporation, the nation's second-largest bank holding company, and the Continental Illinois Corporation, the seventh-largest, yesterday reported sharp declines in their fourth-quarter net income. BankAmerica said its net income declined 32 percent, to $53 million, from $78 million a year earlier. On a per-share basis, net income dropped 54 percent, to 22 cents from 48 cents. Net income was substantially bolstered by a gain of $31 million from a swap of debt for equity.

For all of nuclear power's well-publicized troubles, a surprising number of industry experts contend that, on paper, nuclear power is still a good bet. In many parts of the United States, they say, nuclear retains a modest economic cost advantage - perhaps 10 percent - over coal, America's most obvious alternative in generating electric power. But that is on paper. In the next breath, the experts acknowledge that even a substantial savings per kilowatt-hour is not nearly enough. So great are the uncertainties, and so huge the sums at stake, that only an irresistible cost advantage could entice the utility companies to continue down the path of nuclear power. ''It's really a very easy choice,'' said John C. Brennan, senior vice president of the American Electric Power Service Corporation, a company that owns many Middle West utilities. ''Nuclear entails too much up- front capital, too much risk, and too much delay in selling our 'product.' ''

S' NIGERIA CALLED GARDEN OF GRAFT By CLIFFORD D. MAY LAGOS, Nigeria, Jan. 19 - A former high-ranking official in Nigeria's recently ousted civilian Government, the story goes, went to a leading British insurance company to arrange for coverage of his English vacation home. The underwriters said they would be happy to insure the house and everything in it - except for the bathtub. The bathtub, they suggested, would be best left in a bank. Made entirely of gold, its appraised value was $5 million. One Western diplomat here says he knows the story to be true. Two others say they have reason to believe it. The story, which has become legend and is heard from foreign businessmen and diplomats here as well as from some Nigerians, is used as an example of both the scope and style of the corruption that became prevalent under President Shehu Shagari.

At the School of American Ballet in Lincoln Center, the brown corridors are jeweled with antique prints and engravings depicting imperial St. Petersburg, 19th-century costume and stage design, French theater and opera. The rehearsal studios are more reminiscent of the old corral - lined on four sides with three-tiered wooden barres to fit dancers aged 8 to 20. Here, on the third floor of the Juilliard School building, is the home base of 325 youngsters, including those made visible to New York City Ballet audiences in ''Coppelia,'' ''A Midsummer Night's Dream,'' the current ''Harlequinade'' and - for 30 years - ''The Nutcracker.'' Last night, a 60-student ensemble performing a waltz from ''The Sleeping Beauty'' shared center stage at the New York State Theater with the City Ballet in the School of American Ballet's 50th-anniversary gala.

PEOPLE dispirited by snow, slush and sleet tend toward reveries of sun-soaked beaches and lush greenswards. It is such fancies as these that New Yorkers can indulge in to their hearts' content during a 12-week round-the-world film retrospective beginning Sunday at the Regency Theater, Broadway and 67th Street. The series offers 59 movies produced from 1922 (''Nanook of the North'') to 1979 (''Tess''), about half of them in Technicolor and all but five long ones in double bills. The action roams from Argentina to Afghanistan and Australia, with frequent side trips to Paris, London and Rome. The films will be at the Regency (724- 3700) through April 7. The criterion for the entries was ''movies with distinctive locations that advance the plot,'' according to Frank Rowley, who has charted 43 thematic retrospectives as the theater's programmer-manager since 1976. The top admission charge is $5, and a $15 series card is available for five admissions.

The United States, citing ''positive developments'' in Poland, has eased two of the economic sanctions imposed in 1981 when Warsaw declared martial law. In response to an appeal from Lech Walesa, the founder of Solidarity, President Reagan restored the right of Polish vessels to fish in American waters and the right of a limited number of charter flights to land in the United States, according to an announcement today at the White House. Regularly scheduled flights remain suspended. The President's spokesman, Larry Speakes, said the changes were in response to ''a general improvement in conditions there.''

''It's important to be a Sister of Mercy in reality even if you may have to forfeit being one in name.'' - Sister Arlene Violet, giving up her religious vows to run for Rhode Island Attorney General. (A14:2.)

A regulation recently adopted by the Comptroller of the Currency that prohibits states from limiting the fees that banks may charge for consumer services is being challenged by Federal and state legislators, state banking officials and a consumer advocacy organization. In the latest direct challenge, a group representing state banking officials called on the Comptroller yesterday to ''immediately'' rescind the regulation. The group, the Conference of State Bank Supervisors, contended in a letter delivered to Comptroller C. Todd Conover that the rule was ''unlawfully adopted'' and ''substantively invalid.'' The officials, and other critics of the new rule, contend that it was put into effect by the Comptroller without prior publication and a period for public comment, a violation of Federal law. Mr. Conover, who signed the rule change on Nov. 28, has maintained that the rule is valid and that it was legally adopted.

The Islamic Conference voted to readmit Egypt. That nation's membership had been suspended after it signed a peace treaty with Israel in 1979. (Page A1, Column 6.) Sanctions against Poland were eased by the Reagan Administration because of ''positive developments'' in that country. In response to an appeal from Lech Walesa, the right of Polish fishing vessels to work in American waters and the right of a limited number of Polish charter flights to stop at United States airports were restored. (A1:5.)