A new bill from a key Republican senator would provide paid family leave — in return for giving up Social Security benefits.

The legislation, from Sen. Marco Rubio, the Florida Republican who unsuccessfully sought his party’s presidential nomination, is notable both for demonstrating broader interest in the concept of paid family leave as well as the idea of drawing from Social Security.

Under Rubio’s proposal, dubbed the Economic Security for New Parents Act, parents could apply for at least two months of leave across their household. His office calculates the benefit is large enough that many families will be able to finance at least three months of leave.

Expectant parents would apply to the Social Security Administration, and after the birth or adoption of their child and the provision of additional documentation, they would receive two monthly payments of equivalent size.

Estimated benefits from Sen. Rubio's Economic Security for New Parents bill. Sen. Rubio

The cost, Rubio’s office calculates, will be a 3-to-6 months delay in receiving Social Security benefits.

Ivanka Trump, the White House adviser who is the daughter to the president, has been lobbying Congress for it. Most industrialized nations do have paid family leave, as do six U.S. states as well as Washington, D.C.

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The Independent Women’s Forum, the conservative group which provided the blueprint for Rubio’s proposal, says the Social Security Administration already has experience under which workers can accelerate or defer retirement benefits.

It calculates the impact on Social Security’s finances would be small — perhaps 2 million parents receiving $7 billion in benefits a year, compared with the $950 billion in payouts Social Security makes each year.

The Urban Institute, in its own analysis, came up with similar numbers on the impact to Social Security and estimated delay to getting retirement benefits. But the group warns that using Social Security in such a way could erode the program.

“By setting a precedent of allowing beneficiaries to borrow against their future Social Security benefits to finance nonretirement needs, however, the paid leave program could lead to other similar programs, such as ones to finance student loan forgiveness or midcareer educational investments, which could undermine Social Security’s ability to ensure basic retirement security for all Americans,” the group wrote.

Kathleen Romig of the Center on Budget and Policy Priorities makes a similar point. She points out that the way Social Security currently works, if someone accesses it more than once — say for a disability, and then later for retirement — there is no penalty attached for the additional use. “Some people will have more of these events than others, and that’s just how it works,” Romig said.

Since women disproportionately take leave — where they already pay a penalty from resulting losses of wages, retirement savings and future Social Security benefits — the cost would be disproportionately put on them. “It just asks women, once again, to bear the burden of childcare costs,” Romig said.

The states that have family leave, like California, fund the benefit through payroll taxes instead.

Elements Romig does like of the Rubio plan are its federal nature as well as the usage of the Social Security infrastructure, since it already maintains information on births and worker pay.

“Using the Social Security system to deliver this makes total sense,” she said.