(Reuters) - A judge in Tennessee is offering inmates at a county jail reduced sentences if they agree to undergo a free vasectomy or insertion of a birth-control implant, drawing fire from opponents who say the program violates fundamental constitutional rights.

The voluntary program, which offers White County Jail inmates 30 days off their time behind bars, aims to cut the number of children who are born drug-dependent or end up in foster care, Judge Sam Benningfield said on Friday.

“It is in no way a eugenic program,” Benningfield said in a statement. “Sterilization is never involved and is not an option as all procedures offered are reversible.”

The American Civil Liberties Union of Tennessee has denounced the program, describing it as a “so-called choice” between jail time and “coerced” contraception or sterilization.

“Such a choice violates the fundamental constitutional right to reproductive autonomy and bodily integrity by interfering with the intimate decision of whether and when to have a child,” its executive director, Hedy Weinberg, said in a statement on Wednesday.

Benningfield said the idea grew out of an earlier program he created with the state’s Department of Health under which inmates’ sentences were reduced by two days if they completed an education program on the risks of raising children while using illegal drugs.

The judge’s new order took effect on May 15 but did not gain wide attention Nashville’s News Channel 5 aired a story this week.

So far, 32 women have received the birth control implant, which prevents pregnancies for up to four years, and 38 men were awaiting a vasectomy, the station said.

The program was originally aimed at women who might give birth to drug-addicted children, but it was expanded to men to avoid discrimination, Benningfield said.

No men under the age of 21 can participate, the judge added in his statement, and those eligible must complete a full physical exam and wait 30 days before the procedure.

Benningfield said that for inmates and former inmates, “Unplanned and unwanted children and the resulting obligations complicate their lives and make their reintegration into society more difficult.”

A spokeswoman for Tennessee’s Department of Health said it does not support the new program and that neither it nor the White County Health Department were involved in developing it.

“We do not support any policy that could compel incarcerated individuals to seek any particular health services,” the spokeswoman, Shelley Walker, said in a statement on Friday.