5 months ago
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People who have children are more likely to live to the age of 76 - with two offspring appearing to be the most beneficial, a new study suggests.
Researchers from the University of Michigan carried out a review of the genetic and health information of 276,000 people living in the UK.
They discovered that genetic variants linked with higher reproduction have become more common in recent decades.
And they found that having children appeared to be associated with a higher likelihood of surviving into older age.
Professor Jianzhi Zhang, one of the study's authors, said: 'One thing that is relatively clear is that having children is more beneficial to longevity than not having children at all.
Researchers at the University of Michigan have found that having children appeared to be associated with a higher likelihood of surviving into older age (Stock image)
'What we measured was the probability of living to the age of 76.
'Those with children have a 5-10 percentage point advantage over those without children.
'Interestingly, we found that... having two kids corresponds to the longest lifespan. Having fewer, or more, kids both lower the lifespan.'
While their study did not examine possible reasons for this, Professor Zhang said other research has suggested a link between having children and social contact.
'Previous studies found that people with children tend to have more social interactions, such as interactions with other parents and teachers, and higher social contact is known to be linked to longer life,' he added.
'It is possible that having two children strikes a balance between having a good amount of social interactions and not having too much economic or physical burden.'
Surprisingly, the study also seemed to suggest that the genetic mutations linked to reproduction - making people more fertile - were also linked to a shorter lifespan.
This supports a decades-old evolutionary theory, first proposed by biologist George Williams in 1957, that genetic mutations that contribute to ageing could be favoured by natural selection - and passed down generations - if they are advantageous earlier in life in promoting earlier reproduction or the production of more offspring.
While their study did not examine possible reasons for this, Professor Zhang (Pictured) said other research has suggested a link between having children and social contact
However, the researchers - whose findings have been published in the journal Science Advances - said that both the ability to have children, and lifespan, are affected by both genes and the environment.
And compared with environmental factors - such as the impacts of contraception and abortion on reproduction, and medical advances on lifespan - the genetic factors actually play a relatively minor role.
A previous study indicated that women who have had several children could be at reduced risk of dementia.
Experts have discovered that higher exposure to oestrogen throughout a woman's life could lead to a healthier brain.
Those with a longer 'reproductive lifespan', or who have had several children, accumulate a higher exposure to the hormone.
And this appears to lead to a lower risk of cerebral small vessel disease - a condition that results from damage to small blood vessels in the brain and is linked to cognitive impairment and dementia.
