BOSTON, JULY 2 -- David and Ginger Twitchell, lifelong Christian Scientists charged with manslaughter for allowing their toddler son to die rather than seeking medical help for him, heard themselves depicted today as loving parents and reckless religious zealots.

The descriptions came in hour-long closing statements by lawyers in the hard-fought, 11-week trial in Suffolk Superior Court. Widely seen as a test case of parental duty and religious freedom, the trial focused on whether the Twitchells broke the law by relying exclusively on "spiritual healing" to treat their son, Robyn, 2 1/2, who died of an obstructed bowel April 8, 1986.

"What religion was the baby?" special prosecutor John Kiernan asked the jury in his summation, arguing that the Twitchells "sacrificed" their son in order to prove their spiritual purity. "They were on a frolic of their own, an intellectual pursuit."

Defense attorney Rikki Klieman contended that a bowel obstruction is an elusive medical problem presenting symptoms that can fool even experienced doctors. When the child became ill, the Twitchells followed the teachings of their church and sought help from a Christian Science "practitioner," a specialist in healing through prayer.

"They did everything they were supposed to do . . . . they're the last people who ought to be on trial," Klieman said. "The basic foundation of Christian Science is spiritual healing. Without spiritual healing, you do not have Christian Science."

After hearing instructions on the law from Judge Sandra Hamlin, the jury of seven women and five men, along with two alternates, began deliberations today. The jurors have been sequestered since Saturday.

David Twitchell, 35, sat stoically through the closing arguments, occasionally shaking his head in dissent during the prosecutor's remarks. His wife, Ginger, 34, sat with her eyes shut and appeared to be near tears. The couple, who lived in the Hyde Park section of Boston in April 1986, live on Long Island in New York. If convicted, they could be sentenced to as many as 20 years in prison.

The most dramatic testimony in the trial came June 4 when David Twitchell acknowledged that he would turn to medical science if he had it to do all over again. "If medicine could have saved him, I wish I had turned to it," he said during lengthy and often tearful testimony.

In the teaching of Christian Science, a religion founded by Mary Baker Eddy in Boston more than a century ago, bodily illness is considered a manifestation of ignorance, evil and sin that must be attacked through prayer.

But under questioning by Kiernan, Twitchell admitted that, when he had a serious toothache in 1983, he tried to treat the problem with prayer but eventually went to a dentist, who administered Novocain and performed a root canal.

In his closing argument, Kiernan reminded the jury of Twitchell's choice of medical help for himself. He also noted that Ginger Twitchell had received a painkilling medicine during childbirth.

"What allows them to use a doctor for themselves and not for their boy?" Kiernan asked. "Where do they justify that? No one can justify that."

The two sides differed sharply over the Christian Science church's position on doctors. Kiernan argued that Christian Scientists who consult physicians are not expelled, rebuked or shunned by the church, and he cited church documents saying members are "free moral agents" who can visit doctors.

The Twitchells' attorney, however, said that was not an option. "If you call the doctor, it is a true crisis of faith," she said, suggesting that church officials bear ultimate responsibility for Robyn's death.