Older fathers with assisted reproduction: a risk?

More children are being born via assisted reproduction technology (ART). But some countries are imposing an age limit for men. Rightly so?

Assisted reproduction and parental age

Declining quality and quantity of sperm

Dr Annabelle Gourinat and her team wanted to know how male age affects fertility and thus the success of ART. Secondly, they investigated the influence of the fathers' age on the health of their offspring.

The spermiogram showed consistently in many studies that the older the man, the lower the semen volume and the motility of the sperm. From the age of 45, the volume of the ejaculate decreased by 0.22 ml every 5 years. From the age of 40, sperm cells lose 0.5-0.6% of their motility every year.

Effect on pregnancy remains questionable

However, it remains unclear whether the altered sperm parameters also have an effect on a pregnancy and birth rate. Some studies suggest that successful pregnancies and births decrease with increasing paternal age, but others find no correlation. The authors also point out potential biases that could distort the study results.

The situation is similar for the risk of chromosomal aberrations. While the link between maternal age and the rate of aneuploidies such as trisomy 21, 13 and 18 is considered proven, the father's age remains questionable as a potential risk factor.

Higher risk of genetic and psychiatric disorders

The situation is different for autosomal dominant diseases such as achondroplasia and Apert syndrome. Here it was found that the risk of having a child with achondroplasia is twelve times higher in men over 50 than in young men. In the case of Apert syndrome, it was 9.5 times higher.

The scientists also found evidence that the age of the father plays a role in psychiatric disorders. For example, the risk of having an autistic child was about 6 times higher in men over 40 than in men under 30. From then on, the risk increased by a further 21% every 10 years. In the case of schizophrenia, the risk was lower, but increased almost twofold from the age of 50 compared to young fathers under 25.

Paternal age of secondary importance overall

Overall, the literature research suggests that paternal age also has a certain influence on pregnancy and the health of the offspring. However, this does not yet explain the exact pathophysiological mechanisms. The authors also point to the many confounding factors that make it difficult to clearly assign risk factors.

One thing is clear: the main risk factor remains maternal age, which is decisive for the success of assisted reproduction and for many paediatric disorders.

Informing expectant parents about the risks

The trend is clear: over the last 30 years, the age of both parents has risen continuously. At the same time, assisted reproduction offers many couples the opportunity to have children at an older age. This is not without risks, which are mainly due to the mother's age, but also partly to the father's age. It is therefore important to inform expectant parents about the potential risks. Whether there should be an age limit for men in ART remains a matter for social and ethical debate.

  1. Gourinat A, Mazeaud C, Hubert J, Eschwege P, Koscinski I. Impact of paternal age on assisted reproductive technology outcomes and offspring health: a systematic review. Andrology. 2023; 1-14.