Jerusalem, 5 February, 2026 (TPS-IL) — Israeli scientists have identified a potential new biomarker for the mother-child bond: oxytocin levels measured in scalp hair. The hormone, often called the “bonding hormone,” plays a key role in social behaviors, including attachment and parental care, and the study suggests that long-term oxytocin concentrations in mothers may predict the quality of emotional interactions with their children, Ben-Gurion University of the Negev announced.
“Oxytocin is a hormone secreted during childbirth, lactation, and various social situations,” Prof. Florina Uzefovsky explained to The Press Service of Israel. “Previous research in humans and animals connects it to a host of social aspects, and in particular, parenting. We see that these long-term individual differences relate to the quality of the mother-child relationship.” Uzefovsky heads the university’s Developmental Psychology program and co-chairs its Duet Center for Early Childhood Education.
To explore this dynamic, the study examined 28 mother-child pairs, whose children were on average four and a half years old. Researchers collected hair samples from both mothers and children and measured oxytocin concentrations using the ELISA method (Enzyme-Linked Immunosorbent Assay), a widely used laboratory technique to measure the presence and concentration of specific proteins, hormones, or antibodies in a sample. Hair, growing approximately one centimeter per month, allowed the team to track cumulative oxytocin levels over a three-month period, offering a more stable indicator than saliva, which reflects only short-term fluctuations.
During a 20-minute session of free play, the researchers also assessed the emotional availability of mothers and children using a standardized scale to evaluate maternal sensitivity and child engagement. The analysis revealed a significant correlation between maternal oxytocin levels and emotional availability. High levels in mothers were associated with more attuned and responsive interactions, particularly when children’s oxytocin levels were moderate or low. When children’s oxytocin levels were high, the mother’s influence on the quality of interaction appeared less pronounced, highlighting a dynamic interplay between parent and child in shaping emotional connection.
The study underscores the concept of “biological synchrony,” in which parent and child hormone levels align over time, reinforcing mutual responsiveness. According to Uzefovsky, this challenges the common perception that the responsibility for maintaining the bond rests solely with the mother.
“Even at the biological level, the relationship is not solely the responsibility of the mother, even though mothers are often made to feel like they are the only ones responsible. Rather, both the mother and the child are active players within the relationship at the behavioral and biological levels,” she told TPS-IL.
Previous research measuring oxytocin in saliva or blood had highlighted the hormone’s short-term fluctuations, but measuring it in hair provides a more reliable, long-term indicator. “Oxytocin levels in saliva are very small, which makes them challenging to measure. In hair, the levels are substantially higher, which actually supports more reliable measurement,” Uzefovsky explained. The approach offers a proof of concept for examining stable aspects of biology and behavior that influence children’s social-emotional development.
“We may imagine that this biomarker could be used as another indicator of the efficacy of parenting interventions. We are also interested in expanding this research with larger samples, measuring fathers’ oxytocin levels, and exploring interactions with other hormones, such as cortisol, to better understand parent-child dynamics,” Uzefovsky told TPS-IL.
The study was published in the peer-reviewed European Neuropsychopharmacology.
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