What is Advanced Paternal Age, and What are the Risks?

What is advanced paternal age? And are there risks of being an older father? 

The American Urologic Association defines "advanced paternal age" as over age 40 for the male partner. Advanced paternal age can have several implications, both for fertility (ability to conceive) and the health of future offspring. While paternal age can increase certain risks, many men in their 40s and beyond have healthy children, conceived without difficulty.

What happens to sperm as we age, and why? 

1. Decline in Sperm Quality: As men age, there is often a gradual decline in many of the parameters evaluated in a semen analysis. In fact, several large studies have demonstrated an age-related decline in semen volume, total sperm count, total sperm motility, progressive sperm motility, and sperm morphology. Additionally, advancing age has been found to be associated with increasing sperm DNA fragmentation index. A decrease in testosterone production may play a role in the changes seen in semen parameters, since a healthy testosterone is critical for optimal sperm production. Because of these issues, men older than 40 may experience an increased time to conception compared to their younger counterparts. However, the decline in sperm quality is very gradual - which is why many men even into their 50's and 60's have no issues with fertility. 

2. Increased Genetic Mutations: Sperm DNA can accumulate mutations over time. Older men are more likely to have accumulated a large amount of genetic mutations, which can increase the risk of genetic disorders in offspring.  

3. Increased Oxidative stress: Oxidative stress refers to an imbalance between antioxidants and free radicals (a highly reactive molecule with 1 or more unpaired electrons in its outer shell). Free radicals are unstable, and can damage cells, proteins, and DNA.  When free radicals overwhelm the body's ability to counteract them, oxidative stress occurs. This can contribute to DNA fragmentation, as well as problems with sperm motility and morphology. 

What are the risks in pregnancy and to offspring? 

1. Miscarriage Risk: There is some evidence to suggest that advanced paternal age may be associated with a slightly higher risk of early term pregnancy loss, although this risk is not as well-established as with advanced maternal age.

2. Autism Spectrum Disorders: Some studies suggest a higher likelihood of autism in children born to older fathers.

3. Schizophrenia: There is also evidence linking advanced paternal age to an increased risk of schizophrenia.

4. Rare Genetic Disorders: Conditions like Apert syndrome and other genetic disorders can be more prevalent in the offspring of males with advanced paternal age.