What is the relationship between age and fertility in men?


There is a common misconception that it is only female fertility which declines with age, but in reality, men are also affected. It is undoubtedly a fact that the changes in fertility in women are more noticeable such as the menopause which can lead to hot flushes and changes in mood. However, although men may feel invincible, the biological clock is also working against them, especially after they pass the age of 35.

As Bangkok’s leading male fertility clinic, we understand the pressure than many men feel when it comes to their partner becoming pregnant. If the problem does fall with the male partner, there are several things that we can do that can help you and your wife or girlfriend to have a baby. While we can’t term back the clock, in this article, we will explore the relationship between age and fertility in men and what can be done to address the problem.

When does semen quality peak and start to decline?

Soroka University in Israel conducted a study into the quality of semen in normal males in different age groups. It was a detailed study which took into account how often couples enjoyed sexual intercourse, noting that those who abstained for long periods had lower quality semen than those who climaxed frequently.

The conclusion was that the quality of a man’s semen peaked between the age of 30 and 35 with the consensus being that this was nature’s way of encouraging couples to start a family before the man reaches 35. There was a noticeable decline in semen quality after the age of 55 with chances of the male partner being able to produce semen of sufficient quantity and quality in order to father a child, being appreciably lower.

The relationship between age and sperm motility

The study by Soroka University also found that there was a correlation between age and sperm mobility (how well the sperm can swim). Motility was far superior in younger males, but this time it was in those under the age of 25. Once again, 55 was the age when significant changes in sperm motility were noticed with the study revealing that the number of healthy, mobile sperm in men over 55 was 54% lower than those in the 30-35 age group. The variations could not be attributed to the number of times a couple had intercourse.

Genetics also plays a role

A separate study which was conduct by Lawrence Livermore National Laboratory (LLNL) and the University of Berkley in California found that genetic defects in the male’s sperm also became more pronounced with age. While this naturally meant that these men were less fertile, there was also an increased chance of miscarriage; stillbirth and the child have some congenital disabilities – all problems which can be heartbreaking and traumatic for couples.

Genetics problems were also compounded when the female partner was older, which would generally be considered as over the age of 35. In couples where the female was over 40 and the male partner was over 55 genetics problems were a more common feature. The chances of a child being born with Down syndrome increased. Indeed, 50% of children born with Down syndrome to parents in these age groups received the defective gene from the paternal side.

Sadly, Down syndrome isn’t the only disorder that is more prevalent in children born to couples where the paternal partner is older. Achondroplasia (a form of dwarfism), bipolar disorder, schizophrenia, autism and childhood leukaemia were also found to be far more common.

The combined ages of partners is also a factor

When couples are experiencing fertility problems, it is common for there to be an assumption that the problems lie with either or partner rather than the pair combined. The combined ages of a couple are also a factor with arguably the woman’s age plays a more significant role. As both partners aged, particularly the female, the odds of conception on the woman’s most fertile day reduced with age, and this was a constant regardless of other factors.

Women who were in the 19 to 26 age group had a 50% chance of conceiving on their fertile day while those in the 35 to 39 the chances had dropped to just 29%. In couples in this latter age group, where the man was five or more years older, the chances fell to 15%. Therefore, the combined age of the partners is perhaps a bigger factor than had previously been assumed.

The correlation between the man’s age and IVF success

While the chances of having a baby naturally are reduced as the male partner ages, unfortunately, the same is also true for IVF success rates. However, there was some favourable news for affected couples as Intracytoplasmic Sperm Injection (ICSI) technology significant helped to reduce the impact of age, giving some much-needed hope for couples.

ICSI involves artificially injecting sperm directly into the egg. In a study of 2,500 IVF cycles where the males were over 55, it was concluded that although the number of high-quality embryos produced was lower, pregnancy rates or the number of complications during pregnancy was unaffected. Another study considered 4,800 IVF-ICSI cycles, where an egg donor under the age of 36 was used. Once again, the results indicated that paternal age was not a factor when it came to pregnancy and live births.

The conclusion was that as ICSI removed the need for sperm to swim naturally to the egg and penetrate, male age did not matter. However, this was not the case with standard IVF treatment or with natural conception.

More information

If you would like more information about the relationship between age and male fertility, or indeed you have any questions at all regarding fertility and fertility treatments, then contact First Fertility. Our team will address any questions that you may have, and, of course, your confidentiality is respected. Please call us on +66 (0) 2 652 0150-4, or alternatively, you can contact us directly via our website.