Whether you choose to breastfeed or bottle feed will not affect your child's IQ, a new large-scale has found.
The researchers monitored children who were breastfed alongside a group who were bottle fed.
They found little association between breastfeeding and having a higher IQ at aged 2, despite previous research which found this to be the case.
The Goldsmith's researchers found that breastfeeding was not related to improvements in IQ up until the age of 16, indicating it didn't help young brains develop better over time.
At the end of the study, after their mothers' ages and social status was taken into account, both sets of children had an average IQ of 100.
The researchers expected to see differences in IQ between the infants who were breastfed and those who were bottle fed at an early age.
Although breastfeeding was associated with a small IQ advantage for girls aged two, this had evened out by the age of seven.
Study co-leader Dr Sophie von Stumm, from Goldsmiths, University of London, told the Telegraph: "Children - and adults - differ in their cognitive abilities, and it is important to identify factors that give rise to these differences. But comparatively small events like breastfeeding are very unlikely to be at the core of something as big and complex as children's differences in IQ.
"Instead, children's IQ differences are better explained by long-term factors, for example, children's family background and their schooling."
Researchers used data from the Twins Early Development Study, which was originally set up to look at the impact of "nature and nurture" with identical twins and non-identical twins.
Although breastfeeding did not show a positive correlation with a child's IQ, researchers stressed there were other benefits such as improving a child's immune system.
Stumm added: "Mothers should be aware that they are not harming their child if they chose not to, or cannot, breastfeed. Being bottle fed as an infant won't cost your child a chance at a university degree later in life."
In March, Brazilian researchers studied 3,500 babies and found that those who had been breastfed for longer went on to gain better scores in adult IQ tests.
Dr Horta told the BBC breast milk may offer an advantage because it is a good source of long-chain saturated fatty acids which are essential for brain development.
Janet Fyle Professional Policy Advisor at The Royal College of Midwives said: "This is another research report among many studies on breastfeeding and child outcomes.
"While this study adds to an already existing body of knowledge about breastfeeding, our advice remains the same, breastfeeding has many positive benefits for a child’s health and well-being in both the short and longer term.
"We also know of its beneficial impacts on the health and wellbeing of the mother.
"The important issue is to ensure that women have access to skilled advice and support to help them to initiate and sustain breastfeeding for longer.
"Given the increasing focus on public health, we should be doing all we can to encourage mothers to breastfeed and that includes investment in staff."