What was going on when I was born?

The Government today lowered the maximum interest rate on federally backed home mortgages to 13 percent, from 13.5 percent. The reduction in the closely watched rate halts a trend of increases that began in early June, when it stood at a three-year low of 11.5 percent. The new 13 percent rate is effective on single-family home mortgages insured by the Federal Housing Administration and the Veterans Administration.

The tentative agreement to end the nationwide strike against the American Telephone and Telegraph Company is likely to lead to slightly higher phone rates because wage increases will be passed on to consumers, company and union officials and analysts said yesterday. However, the rate increases, of perhaps a few percentage points, would be small compared with those already expected from the structural changes taking place in the telephone business as a result of the pending breakup of A.T.& T. and recent decisions by the Federal Communications Commission. Those changes are expected to lead to at least a doubling of local telephone rates in the next year or two. ''It's fair to assume that if wages go up, rates will go up a commensurate amount,'' said Paul L. Gioia, chairman of the New York State Public Service Commission, which regulates telephone rates in the state. He added, however, ''If wages go up 5 percent in one year I don't think that's significant. That's in line with general economic circumstances.''

Informed that he was engaging in unlawful activity and could get a summons, Antoine Williams moved on. Antoine explained that receiving a ticket would be no small matter. He would be in trouble with his mom. Antoine, who is 7 years old, was playing football on the lawn of an apartment building, an activity strictly prohibited by the latest edict from Mayor Thomas H. Cooke Jr. in his ''war on blight.'' The Mayor cracked down a few days ago on ''the spectacle of young children'' playing outside apartment buildings and on their turning the nice, green lawns here into ''dust bowls'' and ''pigpens.''

Quotation of the Day ''The debates represent a breakthrough in the way the Democratic Party selects its Presidential candidate.

International A new trade-policy dispute has erupted within the Administration. The subject is an export license sought by a British-owned Houston-based company to ship a $40 million offshore marine mooring system to Libya. The Commerce Department is in favor of the sale, officials said, while the State Department opposes it. The dispute comes just days after the resolution of one dealing with sales of pipeline-laying equipment to the Soviet Union. (Page A1.) Mexico, after a year of financial crisis, has overcome an early sense of panic and is now resigned to a combination of economic difficulties and the social hardships they have created. Along with austerity, however, there is cautious hope for the future. (A1.) Mexico announced compensation terms for 11 of the 57 private banks and credit institutions that were nationalized last year. (D15.)

International Ferdinand E. Marcos appeared on television to try to dispel what he called ''an orchestrated attempt to spread panic'' across the Philippines after the assassination Sunday of Benigno S. Aquino Jr., his leading opponent. President Marcos said the assassin had fired from a distance of ''16 to 18 inches.'' Opposition leaders said they were determined to fight dictatorship. (Page A1, Column 6.) President Reagan's planned visit to the Phillipines in November is still scheduled despite the assassination of Mr. Aquino, according to the chief White House spokesman. (A8:1-2.)

Mayor Koch announced yesterday that he had ordered medical examinations of 7,000 children in 50 welfare hotels in New York City and that the examinations would begin today. His action followed surprise inspections of two city hotels housing displaced people that Governor Cuomo said had found ''mind boggling'' health conditons. The Mayor, flanked at City Hall by the city's top health and welfare officials, also ordered a study within 30 days on how the city could speed services to these families and whether they could be relocated to permanent housing more quickly. City welfare officials sought to dismiss many of the suggestions made in the inspection team's report to the Governor.

ON a mission cloaked in secrecy, an F-15 jet fighter is now set to soar to the fringe of the earth's atmosphere and unleash an 18-foot missile that is designed to speed into space at the blistering pace of more than eight miles per second. The historic launching, which defense sources say will probably take place before the end of the month, will mark the first flight test of this sophisticated new addition to the American arsenal. In battles of the future, waves of such projectiles might hurl into space to wipe out scores of satellites orbiting the earth, leaving an enemy deaf, dumb and blind. The American decision to move into an era of satellite killers has been hailed by many military people and denounced by advocates of arms control. Congressional doves, condemning it as a giant step in war-fighting technology, nearly stopped the antisatellite weapon (ASAT in military jargon) in its tracks this summer and vowed to continue the fight until its funds are cut from the Pentagon budget.

FOR many students, especially members of minority groups, the community college, with its policies of open admissions and low tuition, has been a vehicle for upward mobility, a point of entry into a higher education system in which black and Hispanic enrollment was only about 5 percent less than 20 years ago. The proliferation of community colleges in the 1960's and 1970's has been hailed as a main instrument in raising the enrollment of minority students in higher education to the current level of 12.8 percent. But now many educators are re-evaluating the significance of that change. Most notably, they are concerned that a far lower percentage of community college students go on to pursue baccalaureate degrees as compared with students who begin at four-year institutions. Since almost half of all black and Hispanic students in higher education attend community colleges, this raises questions about the meaning of their increased enrollment rate.

helping an endangered species. But this time there's money in it as well. The rules are simple: Watch your step; find a sandplain gerardia (illustrated at right); note its location, photograph it in color, and mail the picture to Dr. Rolf Martin at Brooklyn College.

Governor Cuomo's staff was nearly unanimous. Michael J. Del Giudice, the secretary, told Mr. Cuomo he should go. Timothy J. Russert, the counselor, told him to go. Lawrence T. Kurlander, the criminal-justice coordinator, told him to go. But the Governor did not go. The issue, which has emerged as something of a paradigm of both the strongest and weakest aspects of Mr. Cuomo's administration, was the Governor's decision to cancel a trip on Aug. 1 to the National Governors' Association, a meeting that attracted 40 governors to Portland, Me.

PRINCE FREDERICK, Md. HERE in rural Calvert County, as well as in the slums of Chicago and New York, thousands of doctors who have been educated in foreign medical schools are practicing where the graduates of American universities are reluctant to work. These physicians also are staffing other positions many American- trained doctors deem unattractive, such as the medical branches of the armed services and the Veterans Administration, as well as hospitals, prisons and other facilities maintained by Federal, state and local governments. About 100,000 graduates of foreign medical schools are practicing in the United States and the influx is such that Congress, the American Medical Association and some states, including New York, are trying to stop it with a wide range of legal and professional restrictions. In recent years such efforts have slowed the migration, although about 5,000 foreign graduates continue to arrive each year. But the restrictions have also provoked charges of discrimination from the foreign-educated doctors. Some have complained that government officials and the medical establishment are biting the hands that provide medical care to millions of Americans.