In the Baby’s First Years study, one thousand mothers with low income were randomized to receive either $333/month or $20/month during their child's first four years of life. Using measures of the child’s epigenome — biological mechanisms that regulate how genes are expressed — the researchers found that higher cash transfers caused a small difference in an indicator of children's biological aging linked to better long-term health outcomes. Because of the randomized controlled trial design, the researchers concluded that these changes were caused by receipt of the higher cash transfer, rather than other factors.
"Previous research has shown correlational evidence in other studies suggesting that poverty may accelerate epigenetic aging in children, but correlations alone can't tell us whether intervening can slow that process. So it is notable to see a causal impact of the cash transfers. It supports the notion that addressing childhood poverty is a public health priority to protect long-term health," says lead author Laurel Raffington, research group leader at the Max Planck Institute for Human Development.
Previous Baby's First Years studies found that mothers who received higher cash transfers increased their spending on and time in activities with their young children, and the intervention may have caused increased fast-paced brain activity in patterns associated with subsequent cognitive development. However, no differences have been found in other measures of children's health, cognitive, or behavioral development. The current study demonstrates that even without accompanying psychosocial or nutrition interventions, cash transfers alone can produce small, but potentially important, effects on children's biology.
Epigenetic measures respond to factors such as stress, nutrition, and aging, and have been linked to the pace of adult aging and the timing of disease onset. The differences in children's epigenetics across the two groups were small, and “it remains to be seen whether these differences persist as children grow older,” note senior authors Kimberly Noble and Kathryn Paige Harden. “If these differences do persist,” Noble, Professor at Teachers College, Columbia University, continues, “this work has the potential to inform early childhood interventions aiming to reduce disparities in health, disease, and longevity.” Harden, Professor at the University of Texas at Austin, agreed, saying that, “The fact that we already see differences in four-year-old children in their biological aging is striking.”
There was no evidence of differences in biological aging among the mothers themselves, which is consistent with the theory that the effect may be somewhat specific to the developmental period of early childhood. While these results are encouraging, it is not yet known whether biological changes measured at age four predict long-term health outcomes in adulthood — highlighting the importance of continued follow-up of this cohort.
At a glance
A four-year randomized controlled trial tested whether unconditional cash transfers to low-income mothers could alter biological indicators of aging in them and their children.
In the Baby's First Years study, 1,000 low-income mothers were randomly assigned to receive $333 or $20 per month; by age four, children in the higher-transfer group showed epigenetic markers linked to a slower pace of biological aging.
Because assignment was random, researchers could attribute this effect directly to the cash transfers themselves, even without added psychosocial or nutrition support.
Mothers' own biological aging did not differ between groups, and it remains unknown whether the children's epigenetic differences persist or predict long-term health outcomes.
Nature Human Behaviour
Randomized controlled/clinical trial
Human tissue samples
Effects of a randomized controlled trial of unconditional cash transfers on epigenetic measures of ageing and cognition in children and mothers.
8-Sep-2026