A California judge has ordered a woman convicted of beating her children to have the recently approved Norplant birth control device implanted in her arm for three years.

Tulare County Superior Court Judge Howard Broadman, in Visalia, Calif., found Darlene Johnson, a 27-year-old pregnant mother of four, guilty of beating her children with a belt. As part of a plea bargain with her court-appointed attorney on Wednesday, Broadman sentenced Johnson to one year in county jail and three years of probation.

But on the day of sentencing, Broadman also ordered Johnson to have an array of six rubbery plastic Norplant tubes inserted into her upper arm by June. Johnson agreed to the conditions, but her attorney now says that Johnson did not understand that Norplant must be surgically implanted.

"She had a gun to her head. She was told she agrees or she goes to state prison," said Charles Rothbaum, Johnson's attorney. "She didn't understand what was involved. She had never heard of this procedure before. I had never heard of this procedure before."

The enforced contraception marks the first time a judge has ordered a woman to use the implantable device, which was approved last month by the Food and Drug Administration for sale beginning in February.

Norplant takes the form of six plastic tubes, which are inserted beneath the skin of a woman's upper arm, where they release a steady stream of a synthetic hormone that suppresses ovulation for as long as five years.

The approval of Norplant, the first truly new birth control device in 25 years, has sparked a national debate about its use. The judge's decision in California was criticized by the originator of Norplant and others who fear the device will be forced upon poor or drug-addicted women.

Those concerns were fueled last month when the Philadelphia Inquirer printed an editorial suggesting that poor black women should use Norplant. The ensuing criticism from inside and outside the newspaper led the Inquirer to publish a second editorial apologizing for the first.

In the California case, Johnson is black and Broadman is white.

"The use of Norplant for any kind of a coercive purpose is something I am totally against," said Sheldon Segal of the Rockefeller Foundation, the originator of implantable contraceptives and driving force behind the development of Norplant. "I consider it a gross misuse of the method."

"I told you so," said Arthur Caplan, director of the center for biomedical ethics at the University of Minnesota. "I am not surprised by this, but I find it troubling when reproductive capacity is manipulated as a form of punishment. It sure didn't take long."

Caplan envisions the California action as the first of many attempts by governments here and abroad to coerce women to use Norplant. "There is a climate out there that it is easier to use a drug to change behavior than to use social services to change behavior," Caplan said.

"It seems to me this is plainly unconstitutional," said Rachael Pine, senior staff counsel for the Reproductive Freedom Project of the American Civil Liberties Union in New York. "This is about the worst case I can imagine."

Pine said that previous attempts to force a woman to use birth con-trol have been overturned. The Supreme Court in 1942 ruled against court-ordered sterilization. However, Pine said that there probably have been many cases where a woman agreed to birth control as a condition of a plea agreement. "If we don't know about it, we can't challenge it," Pine said.

"We continue to believe that any coercive use of Norplant or other contraceptives sets a dangerous precedent," said Gary Bauer, a former Reagan White House domestic policy adviser and now president of the Family Research Council. "I am all in favor of creative sentencing, but I would hope the judge could find a more appropriate way to deal with the problem than something like this."

Segal and others agreed that ordering Norplant would set a dangerous precedent, because Norplant is a prescription drug with possible side effects, such as irregular bleeding and headaches, and could be wrong for some women.

"The judge really appears to be going beyond his expertise," Segal said.

Rothbaum said his client, who has diabetes and a heart ailment, may not even be an appropriate candidate for Norplant. He said he will try to overturn the order.

"I think it is an effort by government to say to certain people you shouldn't have children," he said.