fertility decreases
Sperm depletion: The tale of man’s eternal fertility
It is possible to be a father late in life, but you cannot rely on fertility even in old age.
© IMAGO / Westend61
Although the biological clock ticks faster in women than in men, they are not immune to dwindling fertility either. Late happiness as a father is not the rule, but the exception. The problem with aging sperm.
George Clooney was 56 when he became a father for the first time. Peter Maffay followed suit for the third time at the age of 69 and Richard Gere was already 70 with child number four. There are men who can still look forward to having children even in advanced and old age. But being a late father is not a matter of course. The biological clock is also ticking in men.
It is true that women have less time to have children than men. While men are constantly forming new sperm, women are born with a certain number of egg cells and no more are produced over the course of their lives. This number of egg cells decreases continuously from birth. While there are initially around one million egg cells, at the beginning of puberty there are only around 300,000. From around the age of 35, the quality of the remaining egg cells also decreases. By the age of 40, one in 100 women has exhausted their egg reserve. As a result, many women are no longer able to have children years before the menopause, the onset of which usually makes pregnancy definitively impossible.
Sperm become increasingly sluggish with age
There is no such fixed point for men. From a biological point of view, they do not become infertile. “In principle, men can father children into old age,” said Professor Sabine Kliesch, director of the Center for Reproductive Medicine and Andrology at the University Hospital in Münster, about “Quarks”. And indeed, men are taking more and more time with having children. In 1991 men in Germany were on average 31 years old when they had their first child, in 2020 they were 34.6 years old, according to figures from the Federal Statistical Office. The time window in which they can father children is also limited. The fertility window for men begins to close around the age of 40 – how quickly this varies from man to man. Lifestyle has an influence on this. Smoking, too much alcohol, cannabis, competitive sports and heat can be detrimental to fertility.
It has been proven that in old age the man, if he is healthy, continues to produce sperm, but that the quality deteriorates. To make matters worse, the spermatozoa become sluggish. You move less and lose speed. The reason: there are more genetic defects in the sperm. According to Kliesch, the more sperm are affected by such defects, the longer it takes for the woman to become pregnant. For example, a British research team found in a study that couples with a woman under 25 and a man over 40 take about three times as long to become pregnant than couples in which the man is under 40. In this case, it takes an average of seven months for the woman to conceive. If conception succeeds despite being older, it can have a negative impact on the health of the child. There is evidence that this promotes mental illness and autism in children.
Male fertility is declining worldwide
The ability of men to reproduce decreases from around the age of 40, explains reproductive medicine specialist Eberhard Nieschlag to the “Focus”. “But at that point you can’t see anything wrong with the sperm. From the age of 50, sperm motility then decreases and this is important for reproduction, otherwise the sperm won’t be able to find the egg,” says Nieschlag. A semen test can clarify how fertile a man is. This tests the fertilization capacity of the sperm. If the results of the spermiogram are abnormal, hormone tests or an ultrasound examination of the seminal ducts may be necessary. Drug treatment can help in some cases, and surgery in others. “In many cases, however, no clear cause for reduced fertility can be found,” can be read on the website of the Federal Center for Health Education (BZgA).
In addition, male fertility is declining overall – worldwide. According to an Israeli study, the average sperm concentration fell by more than 51 percent between 1973 and 2018, from 101.2 million to 49 million sperm per milliliter of semen. The results suggest “this global decline is accelerating in the 21st century,” according to the study, published Tuesday in the journal Human Reproduction Update. The sperm count therefore decreases at a rate of 1.1 percent per year, why it is not known why the sperm depletion occurs. What is clear, however, is that the reproductive ability of men continues to deteriorate as a result.
Source: BZgA, BZgA 2, curds, extra, Focus with material from the dpa