U.S. Defense Secretary Leon Panetta has decided to clear the way for women to serve in many combat positions in the U.S. armed forces, a senior defense official told NBC News on Wednesday afternoon.

The Pentagon chief will announce on Thursday that he is eliminating the direct ground combat exclusion — the Department of Defense policy that excluded women from assignment to units below the brigade level if the unit would be engaged in direct combat.

This will allow women to be assigned to select positions in ground combat units at the battalion level, opening approximately 237,000 individual jobs to women across service branches, including 5,000 positions for female Marines in ground combat elements.

"I support it. It reflects the reality of 21st century military operations," said Sen. Carl Levin, D-Mich., chairman of the Senate Armed Services Committee, in anticipation of the announcement. 

"We are moving in the direction of women as infantry soldiers," one senior defense official said. 

Longstanding opponents of lifting the ban on women in combat lambasted the move as a show of "political correctness."

"The point of the military is to protect our country," said Penny Nance, President and CEO of Concerned Women for America Legislative Action Committee, a conservative lobbying group. "Anything that distracts from that is detrimental. Our military cannot continue to choose social experimentation and political correctness over combat readiness. While this decision is not unexpected from this administration, it is still disappointing."

Panetta, who is expected to leave his position as Defense Secretary in February, will call on the military services to study whether it is possible to open all jobs to women, and the services must come back with their individual plans and recommendations by May 15, a senior defense official said.  He will call for all changes to be in place, and women serving in the new roles by Jan. 1, 2016. 

But a senior defense official who spoke to NBC News said they expect exceptions to remain. Elite Special Operations positions in Navy SEALS, Army Rangers, and Delta Force were likely to remain closed to women, the official said, while the Army is likely to open up jobs for female pilots in the elite 160th Special Operations Aviation Regiment. 

Karim Sahib / AFP - Getty Images file

Female soldiers from the US 1st Cavalry on patrol in Baghdad's al-Jihad quarter in this Mar. 21, 2004, file photograph.

Sen. Patty Murray, D-Wash., called the decision "historic."

"In fact, it's important to remember that in recent wars that lacked any true front lines, thousands of women already spent their days in combat situations serving side-by-side with their fellow male servicemembers," said Murray, who heads the Senate Veterans' Affairs Committee. 

In November, a group of women in the military and the non-profit American Civil Liberties Union sued the Pentagon over the policy of excluding women from combat roles. Their complaint argued that they were already serving in combat roles, but not getting recognized for it.

So far, 152 women have died while deployed in support of the wars in Iraq and Afghanistan and at least 958 have been wounded in action. 

"This is really the implementation of a policy that has been a reality for women for years," one senior defense official said.

According to the most recent Defense numbers, there are 1.4 million active duty members of the military, and nearly 15 percent of them are women. 

This new military-wide rule — distinct from a law — will replace the 1994 policy memo barring women in combat roles, which was signed by then-Secretary Les Aspin.

NBC News correspondent Kelly O'Donnell and NBC staff writer Kari Huus and The Associated Press contributed to this report.

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Lisa Bul / AP file

Robert Kosilek sits in Bristol County Superior Court, in New Bedford, Mass., Jan. 15, 1993. Kosilek, now named Michelle, has since undergone hormone treatment for gender-identity disorder.

A federal judge in Boston on Tuesday ordered the Massachusetts Department of Corrections to provide sex-change surgery to a transgender inmate serving life in prison for murder, ruling that failure to do so violated the prisoner's Eighth Amendment right to adequate treatment.

U.S. District Judge Mark Wolf ruled in the case of Michelle Kosilek, born as Robert Kosilek, who is serving a life sentence without the possibility of parole for murdering his wife in 1990. Kosilek who identifies as female, has received hormone treatments and lives as a woman in an all-male prison.

Wolf found that surgery is the "only adequate treatment" for Kosilek's "serious medical need."

"The court finds that there is no less intrusive means to correct the prolonged violation of Kosilek's Eighth Amendment right to adequate medical care," Wolf wrote in his 126-page ruling.

According to The Associated Press, Wolf is the first federal judge to order prison officials to provide the surgery for a transgender inmate.

"This is a very big victory," Kosilek's attorney, Frances S. Cohen told NBC News. Although the ruling is not binding outside the state, she said: "I think it will be very influential beyond Massachusetts."

It was not known whether the Massachusetts Department of Corrections would appeal the ruling.

After Kosilek first sued the department 12 years ago, Wolf ruled that Kosilek was entitled to treatment for gender-identity disorder, but stopped short of ordering surgery. In 2002, Kosilek started a trial of hormones, with the intention of reevaluating the need for surgery. She sued again in 2006.

The department was supposed to reevaluate after one year, according to Cohen.

"In 2006, it became clear that they were not doing this in good faith," she said.

According to the judge's statement, Kosilek's anguish from gender identity disorder caused him to "attempt to castrate himself and to attempt twice to kill himself while incarcerated.”

Prison officials repeatedly cited security risks in the case, saying that allowing the surgery would make Kosilek a target for sexual assault.

But Wolf found that the department's security concerns are "either pretextual or can be dealt with by the DOC." He said it is up to prison officials to decide how and where to house Kosilek after the surgery.

"The DOC has the discretion to make good faith, reasonable decisions concerning security if the surgery genuinely creates or increases any risk to Kosilek or others," he wrote.

The Massachusetts ruling came just two weeks after the American Psychiatric Association published its updated position strongly endorsing access to treatment for transgender and gender variant individuals, noting that they "can benefit greatly from medical and surgical transition treatments."

"There is increased awareness that this kind of care is not particularly special," said Kristina Wertz, director of programs and policy at the nonprofit Transgender Law Center in San Francisco. "It's just medically necessary care. Our prison systems have an obligation to provide medically necessary health care."

This article includes reporting by The Associated Press.

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Hunter Mahaffey

Hunter Mahaffey, a student at Hueytown High School in Hueytown, Ala., says teachers ordered him to remove his stud earrings in February.

Alabama high school student Hunter Mahaffey has won the right to wear his stud earrings to class again.

The Jefferson County Board of Education on Monday voted during a special meeting to repeal a policy that banned male students from wearing earrings. The change will be in effect for the next school year.

The reversal came after the Southern Poverty Law Center sent the school board a letter on April 25 saying that the male earring ban was unconstitutional and discriminatory.

Mahaffey, who just finished his junior year at Hueytown High School in Hueytown, Ala., was told by school officials to remove his simple stud earrings on Feb. 6, the first school day after he had his ears pierced. The school cited a district-wide policy that “ear jewelry may be worn by females only.”

“I’m really happy to get my ears pierced again and keep them pierced this time,” Mahaffey said in a press release issued by the Southern Poverty Law Center. “I felt discriminated against when the school made me remove my earrings just because I’m a guy. It’s a relief that the school board made the right decision by lifting the ban. Now students have more freedom and equality.”

In a follow-up phone interview, Mahaffey told msnbc.com: “I’m very happy they made the right decision to change it. I plan on getting my ears pierced again during the summer.”

He called the dress-code policy change “a good step forward for my school system.”

Sam Wolfe, attorney with the SPLC, said the case is about more than the right to wear an item of jewelry.

“One of the reasons this case was interesting from SPLC’s perspective is it really gets at the idea of gender stereotypes -- that it’s wrong for government or schools to make policy based on gender stereotypes,” Wolfe told msnbc.com.

The education board said it agreed to change the policy after researching other school districts in Alabama and finding that the overwhelming majority allowed wearing of earrings by males and females alike.

"It was determined in these financially challenging times that it was better to spend the tax dollars to meet instructional needs rather than to take on additional legal costs, the Jefferson County Board of Education said in a statement.

"The approved revision is gender-neutral and addresses safety measures, the potential for disruption, and the promotion of a conducive atmosphere for learning.  It is believed by the School District that its students and parents will observe generally accepted standards of decorum and good judgment in their use of earrings and all jewelry."

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Omar Amin

Omar Amin

Updated at 5:55 p.m. ET: An Arizona grandfather says Barnes & Noble discriminated against him and forced him out of a Scottsdale store because he was a male customer sitting alone in the children’s section.

Omar Amin of Scottsdale said he’s still outraged over the May 4 incident and is demanding an apology from the national book retailer. He said he is considering legal action.

On Monday afternoon, Barnes & Noble issued an apology. “We want to apologize to Dr. Amin for a situation in which Dr. Amin was asked to leave the children’s section of our Scottsdale, Arizona store," Mark Bottini, vice president, director of stores for Barnes & Noble, said in an email. "We should not have done so. It is not our policy to ask customers to leave any section of our stores without justification. We value Dr. Amin as a customer and look forward to welcoming him in any of our stores.”

Amin, 73, said he was ousted from the book store after a woman shopper complained to a staff employee, saying she felt uneasy about his presence in the children’s area.

"I did not break any rules,” Amin told msnbc.com on Monday. “There was no sign posted that said men are not allowed in the children's book area."

Amin said he had been looking for books to buy for his two grandchildren, ages 7 and 5, when his cell phone rang. He said he sat on the floor by the windows and spoke quietly to a friend, he said.

Amin said a store employee interrupted his call and said he needed to leave the store.

Arizona's public-accommodations law prohibits discrimination on the basis of gender, according to Arizona State University law professor Charles Calleros.

Calleros told the Arizona Republic that if women without children are allowed to shop in the children's section, "then we arguably have gender discrimination.”

Amin, the director of Parasitology Center Inc. in Scottsdale and an expert in infectious disease, had written a complaint to Barnes & Noble.

“It's not enough. I want my honor restored,” Amin told msnbc.com. “I want to walk back into the store with my head held up high. I did not break any rules. My pride has been scratched.”

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Vice President Joe Biden will lead a Democratic push to reauthorize the Violence Against Women Act, the 1994 legislation that now faces opposition from some conservatives.

Biden will be joined Wednesday by Attorney General Eric Holder, Senior Advisor Valerie Jarrett, White House Advisor on Violence Against Women Lynn Rosenthal and Sharon Love, mother of Yeardley Love and founder of the One Love Foundation, to talk about the need to reauthorize the law.

The New York Times has reported that the law would expand financing for and broaden the reach of domestic violence programs. 

However, it said some Republicans say the measure unnecessarily expands immigration avenues by creating new definitions for immigrant victims to claim battery, and also dilutes the focus on domestic violence by expanding protections to new groups, like same-sex couples.

The Washington Post reported that Biden will be joined by Maryland Lt. Gov. Anthony Brown, a Democrat, whose cousin was killed by her estranged boyfriend in 2008.

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