Atanta Mayor Andrew Young said here yesterday that black parents should take note of Wayne Williams' conviction for the murder of two boys in Atlanta and "beware of the kind of sickness that is getting into our children." Young added that black parents need to give their children strong values as well as the the material benefits that have come to black people with integration and affirmative action.

Young, who was elected mayor of Atlanta last November after the killings had ended, offered his insights into the Atlanta murders at a prayer breakfast at the Washington Hilton given by District Del. Walter Fauntroy. He said he is convinced of Williams' guilt in the wake of his conviction last week. Doubts about the young man's guilt, he said, have to do with the disturbing possibility that Williams--who has been linked to several of 28 unsolved killings of black children--is the nation's first black mass murderer.

In his speech, Young said he met Williams 10 years ago when he was running for Congress and Williams, then 13, interviewed Young for the radio station the teen-ager owned and managed. Young said he thinks he was interviewed at a table in the same basement where Williams is accused of having killed his victims before dumping their bodies in rivers and wooded areas in and around Atlanta.

"Wayne Williams' parents are good, church-going people and they gave their son everything they could," Young said before an audience of about 800 people at the breakfast. "When he was 13 he had a radio station. When we were 13 I was lucky to have a radio. His parents may have given him too much, too many material things . . . He began to think he was his own God. He didn't see himself as a child of God. He didn't see the other children in Atlanta as all God's children. He began to think of himself as God.

"With integration and the progress black people have made," he added, "we cannot start thinking that giving material gifts to children will replace the gifts of spending time and loving them."

Young said there is no question in his mind about Williams' guilt in connection with the 28 murders that terrorized black children in Atlanta from July 1979 to May of last year. Williams was tried by a black judge, Young noted, who grew up in the same Atlanta neighborhood in which Williams lived.

After the speech Young added that there was no way that Williams could blame the verdict on racism.

"All affluence is not progress," Young told a reporter after his speech. "Wayne Williams' problem is not poverty and deprivation. It was overindulgence. There are similarities between the killers of John Lennon, the fellow that shot President Reagan and Wayne. They were all rather intelligent people who had opportunity but somehow did not learn to respect other people.

"As a parent," Young added, "I have to ask myself what does Wayne Williams' case say to me about the time I spend with my children. What am I teaching my children and how firmly do I establish with them a sense of law and justice?"

Young said he believes Williams may have gone to the bridge that night-- where is alleged to have thrown a body off and into the river below--because he wanted to get caught. "Everybody in town knew about the roadblocks on the bridge and the highways," Young told a reporter. "He had to know. For him to go there with that knowledge says there was something in his mind that wanted him to stop."