Elon Musk is on a personal crusade to increase the American birth rate, including his own siring of 11 children with three different women. In part from a similar concern, Vice President-elect J.D. Vance has denounced middle-class “childless cat ladies”; under fire, he claimed he was being sarcastic, but declined to withdraw the comment or its intended complaint. Instead, he has criticized women—singling out schoolteachers—who don’t have their own children and therefore “don’t have a direct stake in this country.” To fix this, he’s come up with the unusual idea of providing an incentive to increase family size by giving parents greater voting rights than adults without offspring, allowing mothers and fathers to cast extra votes on behalf of their minor children.

The U.S. birth rate is now less than half what it was in 1960, when there were 24 annual births per 1,000 people. By 2022, the rate had fallen to 11. While the share of children in the population is decreasing, the share of seniors is rising. As Musk aptly quips, “Sales of adult diapers should never exceed sales of baby diapers.”

He’s got a point. Our lower birth rate is producing an active workforce that will be too small (and, what he doesn’t mention, too poorly paid) to support a growing number of retirees.

In 1960, on average, 100 members of the working-age population (those from 25 to 64 years of age) had to support 20 seniors (65 years and older). By 2020 this old-age dependency ratio had increased to 25. And it is getting worse: Recent estimates suggest the ratio is already approaching 30, as more Baby Boomers retire.

In the long run, reversing 50 years of growing income inequality would somewhat improve the ability of the currently employed to support retirees. This would require higher compensation for lower- and middle-wage workers, a more progressive tax system, and more public investment in manufacturing, housing, and other infrastructure. But none of these policies are likely to be implemented sufficiently to make a big difference in the foreseeable future, and in any case they would not alone fix things as the relative size of the workforce continues to decline.

Nor can the age imbalance be solved by scolding women to abandon careers so they can produce gaggles of children. There is a more realistic and better way—really the only way, at present—to address our demographic problem.

We have little choice but to welcome legal immigrants from low-opportunity nations and do all we can to ensure that their own offspring will be productive enough to pay the taxes needed to support seniors, native and immigrant alike. This means giving those immigrants a path to citizenship and then investing heavily in free prenatal and postnatal services along with public health workers who can help parents become aware of and take advantage of such programs.

Musk favors welcoming skilled high-tech immigrants to replace American workers whom he deems unqualified, but he has not explained what would happen to the American tech workers he would displace. Immigrants now fill more than six million unskilled jobs that Americans shun, including as personal care aides, agricultural and other types of manual laborers, gardeners, and housecleaners. Americans laid off from skilled tech jobs to make way for well-educated foreigners are not likely to shift to the gardening and housecleaning roles that will become vacant under Trump’s deportation scheme.

Many of our unskilled workers now holding these jobs are undocumented, often working informally and not paying taxes. Ensuring more legal immigration to sustain the size of this workforce, legalizing those who are now undocumented, and improving their wages so they can make greater contributions to support our elders is the only way to avoid a demographic disaster. It will also require financing high-quality infant and early childhood services for these legalized immigrants, as well as public schools where teachers are well paid and that are resourced to the level that parents in affluent suburbs take for granted. Indeed, such resources are necessary to make all workers, native and immigrant alike, more productive employees and taxpayers. Initiatives like these would help integrate immigrants’ children into the taxpaying middle class and solve the birth shortfall about which Musk worries.

Simply put, legitimate concern about our coming demographic crisis is inconsistent with a desire to end unskilled immigration and deport the current unskilled workforce.

In theory, our crisis is less severe than it appears because while our active workforce will have to support a growing number of retirees, it will also provide for a smaller number of children—those under 18. The drop in our responsibility to care for the young has been steeper than its growth for seniors—because of our declining birth rate, the child dependency ratio has fallen from 77 in 1960 to 45 in 2020. Including both seniors and children whom working-age Americans have to support, overall dependency declined in that period, from 97 to 70.

Yet a lower combined dependency ratio is no solace. We can’t easily shift spending on children to seniors, nor should we. Our expenditures for K-12 education and other child services are already too low; it would be foolhardy to reduce them further to free up more funds for seniors’ pensions and health care. Further, we pay for Social Security with a national program, but K-12 education is mostly financed by state sales and local property taxes. Without a revolutionary change in the organization of American public finance, shifting state and local education funds to support national retirement programs is inconceivable.

So it remains true that a low birth rate, leading to lower tax revenues from future workforce generations, will greatly impede our ability to support an aging population.

Many Americans are misled about the seriousness of our low birth rate because of a myth about Social Security that was promulgated by President Franklin Delano Roosevelt. When he was persuading Congress to establish the retirement program in 1935, the President offered the American people a nonsensical explanation of how the system would work. To overcome popular opposition to added taxes, he suggested that payroll deductions (and the complementary payments by employers) were not really taxes, but contributions to personal accounts held in trust for them by the government, from which benefits would later be paid upon retirement.

In his message to Congress calling for the retirement program, President Roosevelt said:

In the important field of security for our old people, it seems necessary to adopt…principles: First, noncontributory old-age pensions for those who are now too old to build up their own insurance. It is, of course, clear that for perhaps 30 years to come funds will have to be provided by the states and the federal government to meet these pensions. Second, compulsory contributory annuities which in time will establish a self-supporting system for those now young and for future generations. [emphasis added]

In 1941, an aide, concerned that a future economic downtown might lead to panic because people would assume that if their wages dropped (or disappeared) so too would their Social Security payments, urged the President to end the payroll deduction system that misled Americans that they were contributing to their own individual accounts and to openly finance the retirement system with the same current-year general revenues that fund all federal programs. President Roosevelt replied: “I guess you’re right on the economics. They are politics all the way through. We put those payroll contributions there so as to give the contributors a legal, moral, and political right to collect their pensions…. With those taxes, no damn politician can ever scrap my Social Security program.” The President also explained that because Americans were generally opposed to depending on government for “relief,” they were more likely to support a program that they believed only returned their own contributions than the reality of a retirement program funded by federal revenues.

In truth, payroll deductions of “those now young” were always going to be used for current expenditures, including the pensions of “those who are now too old to build up their own insurance.” And those now young would eventually draw their pensions from federal revenues during their retirement years, including the contributions of workforce participants at that time. Payroll taxes would supply all the federal revenues needed—as long as the workforce didn’t shrink and the cohort of retirees didn’t simultaneously explode in size. Neither the President nor any experts foresaw these developments, nor could they have.

Until now, FDR was correct on the politics. On several occasions when Republicans tried to cut Social Security, their proposals met fierce opposition because many Americans believed that politicians were threatening to take away their personal accounts at the Social Security trust fund. But the low birth rate and enlarged retiree cohort have changed the politics. Soon, when the day comes that there won’t be enough workers contributing to the fictional fund to pay that year’s benefits to the larger number of retirees from that fund alone, fiscal conservatives will be able to exploit the belief in a separate and self-financing retirement system by claiming that the existing program will “run out of money” as benefits being paid out each year exceed the fund’s accumulated contributions.

In truth, the treasury is not running out of money for retiree benefits any more than it is for defense or student loans or anything else. Just like other spending, retirement benefits are funded by current tax revenues (including Social Security payroll deductions) or new debt—and they can always be paid by increasing one or the other. The problem is that a smaller workforce will have difficulty generating enough tax revenues for all purposes. Without greater taxation, whether deducted separately from paychecks or as income and corporate taxes, any additional spending adds to the federal deficit.

At times, the federal government has ignored the purported independence of the Social Security fund and topped up the dollars included in the allegedly separate fund, even if they weren’t contributed by workers for what they think of as their own personal accounts. After the “great recession” that began in 2008, Congress enacted, and President Obama signed, a tax cut as an economic stimulus. But instead of cutting income tax rates, it cut the Social Security payroll tax for two years. To “reimburse” Social Security, the federal treasury credited the fund for the lost revenue. The treasury has also added credits to compensate armed forces personnel for having lower earnings (and thus, lower payroll tax contributions) than they likely would have had in the civilian workforce. And, of course, as FDR acknowledged, the treasury had to pay Social Security benefits for retirees who hadn’t had the time to build up the charade of personal accounts after payroll deductions began. These federal treasury subsidies continued into the 1980s. The only solution to Social Security’s impending “shortfall” is to make new accounting transfers from general revenue to the Social Security fund, and this will be politically impossible without more tax collections from an immigrant-nourished workforce.

The Social Security trust fund that receives payroll contributions and pays retirement benefits is only an accounting gimmick. The tax shortfall, resulting from a workforce getting smaller relative to the retiree cohort, is what Musk and Vance highlight. It’s not only a problem for Social Security, but for all federal programs, whether they have a paper “trust fund” or not. Medical advances have enabled retirees to live and collect retirement benefits for longer. The Baby Boom of the post-World War II decades also created an unusually large group of Americans who are now in or entering retirement. With this bulge of retirees, there are now too few active workers to pay for elderly Americans’ benefits without doing at least one of three things: substantially raising the wages on which workers’ payroll deductions are based; enacting politically unpopular tax increases; or assigning new credits to Social Security from the treasury that would increase the federal deficit. The problem will only get worse as the birth rate continues to decline.

But the Musk-Vance solution—to solve this by getting existing American women to have more children—is unworkable. Some women begin careers and then leave to have children, but even their contribution to the birth rate is reduced because they typically attempt pregnancy at older ages when fertility rates are lower. Some women do freely choose to remain out of the paid workforce to raise large families. But there aren’t enough of them to produce a sufficiently large workforce to support tomorrow’s seniors. We should not attempt to persuade other women to abandon their chosen careers to stay home and have babies. If public figures like Musk and Vance do attempt such persuasion, it will be ignored.

Women now exceed men in college graduation rates, enrollment in medical and law schools, and completion of Ph.D. degrees overall. Growing gender equality in the workforce is one of the advances of the last 50 years of which we should be most proud. Success like this cannot be rolled back. Immigration, combined with services that turn immigrants into successful taxpayers, is the only way forward.

Certainly, we should better secure our borders and enforce immigration laws, including deporting migrants who overstay their visitor or student visas, a bigger share of illegal immigration than border crossings. But at the same time, we can avoid demographic disaster only by attracting more legal immigrants, including those willing to take the kinds of unskilled jobs that this country has, since the nineteenth century, relied upon immigrants to fill.

It won’t be easy to enact policies that not only welcome legal immigrants but provide the economic and social supports to enable them, as well as all lower- and middle-income Americans, to raise healthy and accomplished young people. Those programs will likely cost more than $30,000 annually per child, and this doesn’t include post-secondary education. But those expenses can be covered by the very same thing that will solve our demographic problem: a larger workforce refreshed by immigration.

The resolve of President-elect Trump, his Vice President-elect Vance, and best friend (for now) Elon Musk to reduce, even eliminate, the unskilled immigrant workforce ensures a future fiscal and demographic disaster, including lives of poverty and hardship for retirees.