Babies who are breastfed are more likely to climb the social ladder, according to eyebrow-raising new research.
Children nursed at the breast are likely to be in a higher social class than their dads by their 30s, the study found.
The researchers compared people's social class as kids - based on their father when they were ten or 11 - with their standing as adults, measured at age 33 or 34.
They found that, when background factors were accounted for, breastfeeding upped the odds of climbing the social ladder and cut the chances of a downward drop by around 20 per cent.
The authors of the study, published in the medical journal Archives of Disease in Childhood today, said that it provided evidence of long-term health, developmental and behavioural advantages to children, which crucially persist into adulthood.
They argued breastfeeding enhances brain development, which boosts intellect, which in turn increases upward social mobility.
"There are few studies that look at the long-term outcomes of breastfeeding, but this study shows its long-lasting positive effect," said Professor Amanda Sacker, one of the report's authors and the director of the International Centre for Lifecourse Studies in Society and Health at University College London.
The authors explained: "The results show that breastfeeding was consistently associated with an increased chance of upward social mobility and a decreased chance of downward mobility."
But they noted it was 'difficult to disentangle' if the breastfeeding effect resulted from the nutrients in breast milk or the skin-to-skin contact between mums and their babies.
They added: "Perhaps the combination of physical contact and the most appropriate nutrients required for growth and brain development is implicated in the better neurocognitive and adult outcomes of breastfed infants."
The study looked at data from two groups: 17,400 children born in 1958 and 16,800 children born in 1970. The researchers found over two-thirds - 68 per cent - of babies were breastfed in 1958, compared with just over one in three - 36 per cent - in 1970.