A title and a subject like "Children of Apartheid" lead one to expect more than the documentary CBS News produced for broadcast tonight. But the one-hour report, at 8 on Channel 9, does not fail to alarm and disturb, nor to shine some measure of new light on South Africa and its shame.

Walter Cronkite hosts the program but notes at the outset that most of the interviewing in South Africa was done by producer Brian T. Ellis. He talked with black and white youths whose lives and world views are being shaped by the racist police state in which they live.

Ellis found two 27-year-old women who offer strikingly convenient studies in contrast: Roxanne Botha, daughter of the country's white president, P.W. Botha, and Zinzi Mandela, daughter of African National Congress leader Nelson Mandela, who was jailed by the white regime when she was 3. Mandela talks earnestly about her hopes for freedom -- her father's and her people's. Botha wanders blank-eyed around the family's palatial mansion spouting rationalized dogma and making a pitiful attempt to sing.

"It's not nice to know that people die," she says disingenuously, ". . . but I suppose it's something one has to live with." Shots of big social affairs held at the mansion look like party scenes out of "The Boys From Brazil." This culture doesn't look anything but doomed; the obvious question is whether it will succumb gradually to pressures for reform or drown in a sea of blood.

Some blacks and some whites are girding for, perhaps hoping for, the latter. The documentary does not ignore the violence in South Africa done by blacks to blacks, including the "necklacing," with fire and gasoline, of government sympathizers. One dissident youth dismisses this as "revolutionary justice," sounding as callous as Ms. Botha.

At the other end of the spectrum are die-hard, militant white racists. One, interviewed by Ellis, is a little blond girl. She says the Bible has predicted a racial Armageddon and so it must occur. "God has said that He is with us," she says robotically.

The documentary takes requisite note of hopeful signs -- like an animated debate about government policies inside the walls of an integrated private school -- but the portents are anything but encouraging. Some of those interviewed are disguised, fearful of reprisals. Cronkite says in his introduction that "reports like this one are assembled at some risk." A closing credit thanks South African film crews who helped.

Ellis tries to make some points visually, like cutting from the little blond girl in her back-yard swimming pool to black youths cavorting in a mudhole. Some scenes of police brutalizing blacks and rounding up "detainees" are included, and occasionally an ominous hand reaches up to cover the lens. With censorship policies now in effect, the government raises that hand whenever it can.

Originally the program was to open with Cronkite saying, "This documentary is illegal." A South African lawyer in CBS employ, shown the script, advised that the line be deleted, and it was. Cronkite has said he felt the line to be inaccurate anyway. CBS took some flak for this, but network sources insist the lawyer's review was a standard legal precaution, not an attempt to avoid offending the South African government.

In defense of CBS and this edition of "CBS Reports," and despite a careful Cronkite narration, the program should indeed irritate the South African government. In so doing, it helps make amends for a naive puff piece about the Botha regime that aired on "60 Minutes" a few years ago.