Editor’s note: This article by Rebecca Kheel originally appeared on Military.com, a leading source of news for the military and veteran community.

A push to give National Guardsmen and reservists the same parental leave benefits as their active-duty counterparts is brewing as lawmakers negotiate a compromise defense policy bill.

Four lawmakers from both parties and chambers of Congress sent a letter this week to the leaders of the House and Senate Armed Services committees urging them not to drop a proposal for expanded parental leave for reserve components from the negotiated version of this year's National Defense Authorization Act, or NDAA.

"At a time when we are seeing recruiting and retention challenges across the services, this simple fix helps to ensure that parents are fully supported as they build their families," Sens. Lisa Murkowski, R-Alaska, and Maggie Hassan, D-N.H., and Reps. Zach Nunn, R-Iowa, and Jeff Jackson, D-N.C., wrote in the letter sent to committee leaders Tuesday and obtained by Military.com.

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"Thank you for your leadership and commitment to our nation's service members, and we urge you to continue advocating for service members as they become new parents in the final FY2024 NDAA conference agreement," they added.

Right now, Guardsmen and reservists who are on a drill status can take maternity leave if they give birth. But non-birthing parents, adoptive parents and fosters have no such option.

By contrast, active-duty service members, including Guardsmen and reservists in an active-duty status, can take up to 12 weeks of leave whether they are birthing parents, non-birthing parents, adoptive parents or foster parents. The active-duty policy was rolled out this year after being mandated by Congress.

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To fix the disparity between active-duty and reserve components, Hassan, Murkowski, Nunn and Jackson introduced a bill earlier this year to give Guardsmen and reservists the same benefits. Nunn is in the Air Force Reserve, while Jackson serves in the Army National Guard.

The proposal made it into the House-passed version of this year's NDAA, but was not included in the version of the bill passed by the Senate earlier this year, making it unclear whether it will survive the compromise version that will become law.

A congressional aide told Military.com they did not yet have a sense of whether the parental leave parity provision would make it into the agreement.

Formal negotiations, known as a conference committee, on the NDAA have not officially started, but the leaders of the Armed Services committees -- Sens. Jack Reed, D-R.I., and Roger Wicker, R-Miss., and Reps. Mike Rogers, R-Ala., and Adam Smith, D-Wash. -- have had informal talks. And lawmakers and advocates have started jockeying for their priorities to be included in the final NDAA with letters such as the one from Murkowski, Hassan, Nunn and Jackson.

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"We are pleased to note the past progress made by the Senate and House Armed Services committees in ensuring our service members receive the parental leave they deserve," Murkowski, Hassan, Nunn and Jackson wrote. "However, we must eliminate the disparity for members of the reserve component."

In addition to the letter, Hassan and Murkowski are scheduled to participate in an event with the Bipartisan Policy Center on Wednesday afternoon to tout their proposal.

The provision also has the backing of the National Guard Association of the United States and was identified by the advocacy group as one of its priorities for the NDAA in a letter to Reed, Wicker, Rogers and Smith last month.