The 25 parents who picketed against draft registration in downtown Boston yesterday had not memorized their chants. So they read them off of mimeographed sheets, haltingly, and with some obvious embarrassment. "Mothers, fathers hear our cry! We don't want our kids to die!"

Though hardly noticeable in the midday swirl of the city, the demonstrators marched in a tight circle in front of the McCormack Federal Building for an icy hour and a half.

They waved placards, asked watching policemen to join the line, and eagerly answered question for local t.v. and radio. And, as other participants in this week's demonstrations against the second round of registration have done, they claimed success despite small turnouts and media skepticism.

Robert L. Hernandez, spokesman for Parents Against the Draft, a group headquartered in Brookline, yesterday voiced a common theme of the antiregistration movement: "The press and other people don't realize that this is really just an anti-war movement starting early before we have another Vietnam."

"We all learned a lesson from Vietnam--that you can't take what the government says for granted and wait till people start dying," he added. "We must realize that the registration is only the first step of a war process that could lead to another Vietnam."

On Tuesday, a group of men who fought in that war marched at the Central Square post office and joined in a symbolic attempt to barricade the building with discarded Christmas trees.

Larry Chartienitz, a 34-year-old exMarine, spoke for his organization, Veterans Against Foreign Wars: "I would fight to really defend this country, but no one should willingly sign up to fight for nothing for some politician and have poison put in your body."

Like many Vietnam vets, Chartienitz says that exposure to the defoliant Agent Orange--used heavily by the United States army in Southeast Asia--has damaged his health since the war and may make him susceptible to cancer.

Urged on by leaders such as Hernandez and Chartienitz and organized by the Boston Alliance Against Registration and the Draft (BAARD), the anti-registration troop in this area has maintained a determined effort to publicize what they see as a purely political, and ultimately dangerous and immoral government policy. But the movement is burdened with a pervasive pessimism about the extent of its impact and what its members perceive as a continuing threat of war.

Speaking before the current drive to register 18-year-olds began on Monday, Nora Leyland, a BAARD spokesman, warned that "It looks like we're headed for war one way or the other." She added that her movement could not realistically hope to shut down registration, but would settle for "gaining more publicity and making it as hard as possible for the government to get a draft."

Who's the Enemy

Frank Broadhead, BAARD's director, pointed out recently that one difficulty for his group is finding a clear enemy to oppose.

President-elect Ronald Reagan has promised to end registration and avoid a peacetime draft, yet few BAARD members trust him. Congress, meanwhile has expressed a wide variety of views, particularly on the necessity of a draft to go along with registration. The influx of conservatives on Capitol Hill makes many of Broadhead's marchers nervous.

And finally, there is the confusing issue before the Supreme Court--the constitutionality of registering only men in light of recent drives against sex discrimination. Should anti-draft protesters take a stand on the issue one way or the other?

"We do lack something of a focus, Broadhead admits.