Social Security provides a key financial lifeline for tens of millions of Americans, most of whom get their benefits only after they've retired. For many, paying payroll taxes for decades without seeing any immediate payback seems like a bad deal, especially given the uncertainties surrounding the financial viability of the Social Security program beyond the next 15 years or so.

It's therefore understandable that many Americans would prefer to see a more immediate reward for the taxes they pay into Social Security. That's part of the appeal of recently proposed legislation that would allow people to claim parental leave from Social Security. Yet there's a trade-off involved for parents who would take advantage of this program if it were offered -- and it's one that families might not fully appreciate until after they've already made the decision to sacrifice a portion of their financial future to help with near-term needs.

Woman sitting in a chair holding a baby, with a man looking on, in a room with crib and a bed.

Image source: Getty Images.

The latest on parental leave

Sen. Marco Rubio (R-Fla.) and Sen. Mitt Romney (R-Utah) recently introduced their proposal for providing a form of parental leave tied to a family's Social Security benefits. Under the proposal, dubbed the New Parents Act, families would be able voluntarily to claim paid parental leave benefits from the federal government.

The details of the proposal aren't entirely clear, but the summary of how the program would work provides some rough details. Under the plan, parents-to-be would file applications with the Social Security Administration in order to participate in the program, and the SSA would then verify their eligibility. Parents would then provide further documentation following the birth of the child, and the SSA would then pay benefits as called for by the law and as elected by the family.

Parents would be able to choose to take one, two, or three months of benefits to finance their leave. According to Rubio and Romney, the amount of the benefit would be large enough to let nearly all parents at or below the median household income of roughly $60,000 to take leave with benefits replacing at least two-thirds of their working income. Lower-income parents would likely be able to cover more than three months' worth of leave with the benefit. For households including both parents, coordination of benefits would also be available, allowing limited transfer of benefits between the two parents.

What you'd give up to get parental leave from the SSA

However, the parental leave benefits wouldn't come without a cost. Those who voluntarily choose to receive parental leave benefits would have to elect one of two ways to pay for them. They could choose to increase their full retirement age under Social Security by three to six months "per benefit taken" -- perhaps referring to each month of paid parental leave. Alternatively, they could elect to have their monthly retirement benefits reduced by an unspecified amount for the first five years of their retirement.

Rubio and Romney's proposal isn't the only one on Capitol Hill tied to family leave. Other Republicans have made similar suggestions tied to Social Security, while some Democrats have sought outright expansions of federal benefits to cover paid family leave. Moreover, Rubio introduced similar legislation last year, but Congress didn't push it forward before the midterm elections.

Without details, it's tough to do a full analysis of exactly what the trade-offs involved with electing parental leave under the proposal would be. However, a six-month boost to full retirement age would reduce monthly Social Security retirement benefits permanently by 2.5% to 3.3%. Presumably, the five-year reduction would be somewhat larger in order to front-end the reimbursement. Opponents argue that this reduction would jeopardize new parents' long-term financial futures in exchange for a quick windfall.

Watch Washington for more

For now, with so many competing proposals and a divided government, it's unclear whether any of these parental leave proposals will make it through both chambers of Congress, let alone earn a signature from the Oval Office. Yet as presidential campaigns start to get into full gear, you can expect paid parental leave to become an issue once again, and the proposals tying that leave to Social Security could give would-be parents a tough financial choice to make.