"We’re not living in a 'Mad Men' era anymore, where only women are taking care of infants," Harris said. "It's just completely unserious.
"While his plan would undercut women in the workplace, it also provides no relief to working families," Harris added.
Trump released details of his plan today that would allow for six weeks of paid leave, paid for through savings derived from eliminating fraud in the unemployment insurance program. The plan would be run through the existing program.
Harris criticized Trump's proposal for relying on the unemployment insurance program, which leaves it to states to define the amount of the benefit. Harris said that a Florida mother would get "at most" $275 dollars a week under Trump's plan.
Harris added that Trump's plan amounts to "robbing Peter to pay Paul."
The Trump campaign has said that the proposal would not require higher taxes or shift the burden of financing the leave to employers.
Clinton has proposed a family leave plan that would offer 12 weeks of mandatory paid leave, which includes compensation equal to at least two-thirds of a person's salary. The plan would be paid for though higher payroll taxes on high-income earners.
But another senior policy aide to Clinton, Jacob Leibenluft, said other elements of Trump's proposals for child-care costs — including plans to allow families to deduct such costs and the creation of new child-care savings accounts — disproportionately benefit the wealthy.
"The highest-earning families could deduct 40 cents on the dollar for spending on private schools or other expenses," Leibenluft said.
"Donald Trump’s plan leaves 21st-century working families behind," Harris said. "In terms of his maternity leave plans, his proposal is not just regressive and insufficient, it is demeaning ... to working women."