Evolution vs Older Dads

What does natural selection have against older fathers? The article Evolution is not kind to older dads found on ScienceMag looks further into the truth and reasoning of why kids born to older fathers are less likely to have children of their own.

It is a commonly known phenomenon that as dads get older, their chances of producing offspring without mutations get slimmer and slimmer, however, what is less talked about is the risk that their children then face when having offspring of their own. Some of these mutations can be harmless while others can significantly increase the risk for certain diseases. Colleagues at the University of Göttingen in Germany studied and analyzed census records from 17th and 18th century Germany, Canada and Sweden, as well as from 20th century Sweden. The study showed that in both populations, children born to older fathers had fewer kids of their own that survived past the age of 5. For each decade that a father aged, his children had around 10% fewer children of their own.

According to WebMD, studies have found that those born to fathers 45 and older were more likely to have children with mental health problems (autism, bipolar disorder, schizophrenia, and ADHD) as well as rare genetic disorders, such as dwarfism, due to an increase in mutations in an older man's sperm.

As explained in the article, the daughter of a 17th century farmer may have been cursed with a weakened immune system or a malfunctioning heart, leading to possibly an early death sentence or at least prevented her from having her own children. Being born in the 21st center, however, would dramatically increased the child's chances of a long and productive life thanks to modern medicine. The percentage of Swedish babies that survive up to 1 year of age is above 99%, whereas 200 years ago, fewer than 90% survived past 1 year.

Babies born prematurely or with birth defects are now more likely to live. Well then why do children born to older fathers still show to have fewer kids of their own that survive past the age of 5? Just because kids born to older fathers are surviving longer, doesn't necessarily mean they're able to reproduce properly when they reach adulthood. They could struggle with infertility or have a condition like autism that makes it harder to find a partner. For some it could even be a matter of choice. Parents who are at high risk to have offspring with a certain mutation might decide to adopt instead.

Don't be alarmed, the portion affected by this is still extremely low in respect to the human population. Some scientists still argue that if the reproduction of the children of older fathers is greatly decreased, harmful mutations could make their way out of our gene pool. I really look forward to the findings of new discoveries related to this topic. Maybe in the future there will be more available resources for older men to have their sperm monitored for mutations or to get their sperm frozen and preserved before they grow older than the "age of risk". If this article relates to you or your family members, don't panic, Hugh Hefner had his last child at the age of 66, and his son turned out just fine (well, debatable).

Gene Mutations Passed Down From Older Fathers

An article posted in Health Day magazine explains how it may be possible that older fathers can pass down mutations that cause lower intellect. It is common knowledge that an older maternal age increases the chances of Down Syndrome and other birth defects, but what about paternal age? Research is showing that an older paternal age can result in copy number variations. This study focused on children with an IQ less than 70. The research showed that 70% of the mutations that cause low IQ were passed down through the father. In almost all of the cases these father were approximately two years older than fathers that produced unaffected offspring. Another study shows that out of 118 children, 90 of them had intellectual disabilities that were caused my mutations that were passed down from the father. Higher paternal age was associated with almost all if the intellectual disabled children. The children with intellectual disabilities were found to have copy number variations, and in most cases the children were missing sequences of DNA. The study is still too new to make any definite conclusions but it does seem that a high paternal age leads to a higher risk of having offspring with intellectual disabilities.