The First Amendment, parents, tooth decay, excess government regulations and Sugar Smacks were the issues highligting the opening here today of seven weeks of controversial public hearings on a federal government proposal to severely limit and in some cases ban television advertising aimed at children.

The Federal Trade Commission began the two weeks of hearings here -- which will be followed by five more weeks in Washington -- with the opening volleys from some of the biggest guns on each side of the question.

The emotional proceedings have already raised several key issues that go far beyong the scope of children's television advertising -- esetimated to be a $600 million annual business.

Constitutional questions involving the issue of free speech, and whether or not it extends to children's advertising, and the treatment of children as a special case under existing law have already been raised.

Further, the right of a federal agency to usurp at least part of the parental role is questioned by toy and cereal manufacturers and advertisers, who charge that the FTC is merely trying to expand its powers beyond its legal mandate and become a "national nanny."

Finally, the issue of too much government regulation has also been raised. In an era of increasing calls for a reduction in the role of the federal government controlling the marketplace industry asks if this is not an example of excessive government regulation.

The issue was dramatized in a Connecticut third grade classroom last year when more than half of the class, when asked to spell the word "relief" in a spelling quiz, wrote down "R-O-L-A-I-D-S."

And again, when a kindergarten class was asked to name a new pet turtle, after being told not to squeeze the turtle because it might be hurt, the class was asked to name a new pet turtle, after being told not to equeeze the turtle because it might be hurt, the class overwhelmingly voted to name the animal "Charmin."

Consumers Union representative Harry Snyder opend today's prodeedings by calling for a ban on most forms of children's advertising as a "last resort," because industry efforts at self-regulation in that area have failed.

"For 30 years we have permitted television advertisers to demonstrate that they can sell their products in a manner consistent with the way we want our children treated," Snyder said. "They failed this test consistently," he said, accusing the advertisers of "hucksterism, manipulation and crass abuse of what they callously term the children's market."

Snyder and other consumer advocates claimed that children are unfairly influenced by commercials because they perceive them no differently than regular programming.

"There is no suggestion that the Kellogg company's ads are deceiving of false," shot back Kellogg's attorney Frederic Furth, who was the second witness. "No one is suggesting that Kellogg's is not telling the truth. The real allegation is that because some children can't understand the selling purpose of a TV advertisement, that advertisement is somehow unfair."

Furth said that by proposing a ban, the FTC has put itself in the position of "being both judge and prosecutor," in the proceedings. He referred to a recent U.S. District Court ruling in Washington that FTC Chairman Michael Pertschuk could not participate in the proceedings because he was already biased in favor of a ban and had said so publicly.

The FTC proceeding began formally on April 27, 1978 to complete. Specificly, the proceedings will consider problems posed by advertising for children, and what remedies, if any, the FTC should propose to correct any violation of law that may occur.

The proposal goes back to the beginning of this decade, when two non-profit organizations, Action for Children's Television, of Newton, Mass., and the Center for Science in the Public Interest, of Washington, first filed petitions asking the FTC to take up the question.

The commission will consider several options presented to it by various groups. Its own staff, however, has determined that it is inherently unfair and deceptive to address television advertising to children too young to understand or comprehend what is advertising and what is traditional programming. For purposes of this proceeding, "too young" is defined as 8 years old or less.

The FTC staff has also concluded that it is unfair and deceptive to promote, through television advertising, to children 12 years and younger the consumption of sugard foods associated with tooth decay, "because these commercials may take unfair advantage of the youngsters' inability to comprehend the consequences of tooth deacy or malnutrition."

Consequently the staff has proposed the banning of the type of ads mentioned above, as well as a requirement that television advertising to children under 12 for other sugared products "be balanced by nutritional and health messages funded by the advertisers."

Others, like Consumers Union and the Council on Children, Media and Merchandising, have made similar proposals with slightly different approaches calling either for more comprehensive or more limited bans.