Older dads may have children who live longer lives

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'.