Children born to men who delay fatherhood may live longer, a US study has shown. The findings indicate that as men age, the telomeres in sperm appear to lengthen, offering a protective effect against the cell ageing process - a benefit which could be passed on to future generations.
Using data obtained from a longitudinal study from the Philippines, the researchers observed that not only was paternal age at birth associated with longer telomeres in offspring, but the effect was cumulative across generations, with longer telomeres found in grandchildren of men who reproduced at a later age.
'If our recent ancestors waited until later in adulthood before they reproduced, perhaps for cultural reasons, it would make sense for our bodies to prepare for something similar by investing the extra resources necessary to maintain healthy functioning at more advanced ages', said Dr Christopher Kuzawa, co-author of the study and associate professor at Northwestern University in Chicago, Illinois.
Telomeres act like the plastic caps on shoelaces and prevent DNA strands from unravelling but are slightly shortened each time a cell replicates, which can lead to DNA damage. As a person gets older, the telomeres can become completely eroded, and a number of age-related diseases are due to this.
The results of this study, published in the journal PNAS
(Proceedings of the National Academy of Sciences), suggest offspring of
older fathers may inherit longer telomeres, a feature that is associated with increased longevity. However, the researchers emphasised that environmental factors may also play a significant role.
Dan Eisenberg, the lead author of the study - also from Northwestern University - explained that modern environments, where there are fewer accidental deaths and some men are unable to find a partner until later in life, may have resulted in our bodies adapting from an evolutionary perspective. 'If your father and grandfather were able to live and reproduce at a later age, this might predict that you yourself live in an environment that is somewhat similar', he added.
Eisenberg is hesitant to suggest that the older the father, the better off his children will be, however, as other studies have shown that having an older father can be associated with negative outcomes, such as miscarriage due to increased mutations building up in the sperm with age.
Speaking to AM, an Australian current affairs program, Eisenberg said: 'The net impact of having children at an older or younger age is still not clear but this if the kind of intriguing evidence that while we generally have been thinking about this as a negative impact of having older paternal age... this points to a potential positive'.