Now that Sen. Tammy Duckworth (D-Ill.) is set to become the first U.S. senator to give birth while in office, she is calling attention to the lack of support that exists for parents on Capitol Hill—mirrored by the absence of paid family leave laws for working Americans.

"I can't technically take maternity leave," Duckworth told Politico's "Women Rule" podcast. "Because if I take maternity leave, then I won't be allowed to sponsor legislation or vote during that time period."

The first-term senator is working with Senate leadership to determine how she'll be able to cast votes during the 12-week leave she's arranged to take through her office.

"You are not allowed to bring children onto the floor of the Senate at all," Duckworth said. "If I have to vote, and I'm breastfeeding my child, especially during my maternity leave period, what do I do?...Am I allowed to vote? Can I not do my job?"

The absence of Senate rules catering to women who start families comes to light as women's advocates decry a new family leave proposal by Ivanka Trump and Sen. Marco Rubio (R-Fla.)—one that they claim will end the United States' status as the only industrialized nation that doesn't provide paid maternity leave, but that critics say is a wrong-headed solution to a serious problem that will actually rob women of financial security.

Under Rubio and Trump's plan, new parents could take up to 12 weeks of leave upon the arrival of a new baby—but their time off would be funded by their social security benefits.

"What this really is is a cut to Social Security," Linda Benesch, spokesperson for Social Security Works, told ThinkProgress last week. "The proposal that Rubio and Ivanka are reportedly considering involves an increase in the retirement age of people who choose to take leave. An increase in the retirement age is always a benefit cut."

Duckworth advocates for the FAMILY Act, reintroduced last year by Sen. Kirsten Gillbrand (D-N.Y.), which, as she wrote last week in an editorial for CNN, would create "a universal family and medical leave insurance program that would cost employers and employees less than $1.50 per week for a typical worker."

In her interview with Politico, she argued that women in Congress should promote family leave as an issue of economic stability for families and the nation, contrasting with Rubio and Trump's proposal.

"The more women we get into office, the more family-friendly legislation we're going to have, and the more we're going to get an understanding of the connection between family-friendly legislation and economic well-being for our nation," she said. "We need family leave not because it's the warm and fuzzy and nice thing to do, but because it's better for our economy."