Money, it turns out, really is a good thing. In a striking new experiment, scientists gave low-income American mothers a small monthly cash payment and then watched something remarkable happen: their children's biological aging slowed down. To understand why — and what it means — we need to look at aging from a biologist's point of view.
Aging Starts Earlier Than You Think
We tend to think of aging as something that happens late in life. Biologically, though, the process can begin much earlier. Besides your chronological age, biologists also measure a biological age — how old your body really looks on the inside. One of the most powerful ways to estimate it is the methylation age.
Your DNA carries chemical marks called methylation that change in relatively predictable ways as you age: at some sites, methylation increases; at others, it decreases. By reading these marks, researchers can estimate a person's biological age. This is an epigenetic change — the DNA sequence itself stays the same, but the methyl groups attached to it can influence gene expression and chromatin state, and some of these changes may participate in aging itself.
Over the past decade, a family of similar "epigenetic clocks" has become one of the most widely used and best-validated predictors of health and mortality. With just saliva or blood, scientists can measure a child's methylation age and judge how fast that child is aging.
Poverty Leaves a Mark on Children's Cells
Researchers soon noticed something unsettling: growing up in poverty appears to accelerate childhood aging. A 2021 study in Pediatrics, analyzing 600 children and adolescents aged 8–18, found that disadvantaged socioeconomic conditions at home and in the community were associated with faster methylation aging.
Smaller studies had already pointed to differences in cognitive and brain development between children from low- and high-income families. The higher the family income, the better children performed on measures of language, memory, executive function, and social-emotional skills — and corresponding differences showed up in the neural structure and function of the brain regions supporting those skills. Large bodies of social-science research likewise show income-based gaps in achievement, academic performance, and learning-related behaviors such as attention and self-regulation.
Poverty is entangled with many factors, and pinning down its causal effects on children is hard. But one thing is clear: poverty is a key variable that channels many mechanisms. So scientists asked a bold question — what if we just gave poor families money and saw whether it could reverse some of that harm?
The Experiment: Giving Money Directly to Families
That is exactly what Baby's First Years did. The study recruited 1,000 low-income American mothers and their newborns, then randomly assigned them to two groups: 400 families received $333 per month (about 2,200 RMB), while 600 families received $20 per month (about 130 RMB). Payments began at birth and continued for 76 months — from the baby's birth until three months after their sixth birthday.
For the lucky group, that added up to about $4,000 per year — roughly 18% of their family income. The extra money was mostly spent on things researchers would expect: more children's toys and books (what developmental scientists call early childhood enrichment), and more fresh produce. Meanwhile, the team periodically collected data on the children's physical health, stress, and behavior — including methylation markers, measured from saliva once the children turned four.
The Result: Cash Changed Children's Biological Aging
In a paper just published in Nature Human Behavior, the team analyzed data from 329 mothers and 313 children in the high-payment group versus 448 mothers and 423 children in the control group. The result: the cash transfers produced a measurable effect on children's biological aging.
