The Paternal Age Effect

Dear Dr G,

I like your humorous and witty way in addressing taboos and the awkward subject of sexual health. In the spirit of Fathers Day this weekend, I put forward another taboo question of fatherhood in one’s latter part of life.

My name is Zac, I am 54 years old and I’m in my second marriage. My wife is 32. In my first marriage, my wife and I had three children and they are all in their mid 20s.

I am ready to embark on fatherhood again, in my mid 50s, with my new wife. However, I am rather concerned about “the Mick Jagger” effect.

I read that advance paternal age can be detrimental to the health of babies, including the risk of autism, mental health and even cancers. How strong is such evidence?

In my opinion, it is the ultimate dream of the midlife crisis for men to “do a Mick Jagger”.

Essentially, how many of us have the drive and the will to go ahead?

Hope you can enlighten us with the facts of science.

And of course, Happy Fathers Day!

Zac

Sir Mick Jagger, the 73-year-old front man of the Rolling Stone, confirmed the happy news of pregnancy with a 29-year-old American ballerina.

Jagger is also a great grandfather and will be a father again for the eighth time. He has had children with five different women. His oldest offspring is aged 46 and his youngest son turned 18 this year.

Assissi, the daughter of Jagger’s second offspring, has also delivered a great granddaughter for singer in May 2014. To some of us, the ability to father a child well into your “vintage age” is literary like living the life of a rock star.

To others, this may just sound like an extract from A Nightmare on Elm Street with dire consequences to the next generation.

In reality, how robust is the evidence of the “Jagger effect” on the offspring? After all, wasn’t our grandfather and great grandfathers used to continue to procreate well into their advanced years, as there were no benefits of contraception on those days. Don’t we all turn out right? So, how robust is the evidence of the paternal age effect?

The paternal age effect is the statistical relationship between paternal age at conception and the biological effects on the child. In the 2017 review published in Fertility and sterility, the researchers had studied association congenital disorders, life expectancy and psychological with advance paternal ages.

Some scientists observed the drastic decline of genetic quality of sperm cells with age, and risking a generations of health adversity. Others observed that the total health issues remain negligible, as the paternal age increased for many decades and not seen as a major public health concern.

Several studies in the past have confirmed that paternal age is associated with miscarriage and stillbirth. However, what drew the attention of many experts are the associations with mental health, Down syndrome and the intelligence of the offspring.

The 2017 review concluded a relationship between paternal age with the autism spectrum disorder and schizophrenia. However, the incidence is low and the maternal age factor is also crucial in the matter.

The mechanism behind the causation remains unclear to the experts. However, the upbringing of the child and the relationship with the father is also crucial here.

The association of paternal age with Down syndrome is also observed in the review, but the researchers concluded that the effect is small in comparison with the maternal age effect.

In addiction, the study also pointed out an interesting “U-shaped” relationship between paternal age and low IQs. The highest IQ of the offspring was noted at the paternal age of 25-44. However, fathers younger than 25 and older than 44 tend to have children with lower IQs.

The famous population geneticist James F. Crow described that sperm mutation in older men will have direct impact on the gene pool, carrying forward the mutation for later generations.

He said that the “greatest mutational health hazard to the human genome is the fertile older men”.

The only response Dr G has is from his idol, Mick Jagger himself, who once said: “Anything worth doing is worth overdoing!”

On that note, I wish Zac and all the readers celebrating fatherhood today, an amazing “Mick Jagger” Fathers Day!