Revised 9/10/2026
Published 9/11/2026
A man's sperm production usually continues well into adulthood and old age. With age, however, sperm count and quality can decline, which may affect fertility.
Sperm production may decrease. Sperm production and sperm count may decrease with age. The changes usually happen gradually, and their impact on fertility varies individually.
Sperm quality may deteriorate. With age, sperm motility and normal structure, i.e. morphology, may deteriorate. This can affect the sperm's ability to reach the egg and fertilise it.
More changes may occur in sperm DNA. With age, the risk of sperm DNA damage and certain chromosomal abnormalities may increase. This can affect the success of fertilisation and the risk of miscarriage. In addition, an older paternal age is associated with an increased risk of certain health problems in offspring.
Several lifestyle and health factors can impair male fertility.
Lifestyle changes can improve male fertility in about 3 months. This is the time it takes for sperm to mature in the testis. Even a minor improvement in sperm count and quality can enhance the chances of a successful fertility treatment.
Investigating male fertility begins at an infertility specialist’s appointment, where factors related to health status, lifestyle and previous medical history are reviewed.
Investigating male fertility begins at an appointment with an infertility specialist, where factors related to health status, lifestyle, and previous medical history are reviewed.
If abnormalities are found in the semen analysis, or if there is little sperm or it is completely absent, further examinations can be performed to determine the cause. Further examinations may include a clinical examination by a physician, an ultrasound scan of the scrotum, and checking hormone levels with blood tests.
If necessary, more detailed examinations can be performed on the semen sample, such as a sperm DNA fragmentation examination or Mioxsys examination. Chromosomes and the Y chromosome gene region can in turn be examined from a blood sample if there is cause for it.
Mioxsys test: The Mioxsys test can be used to measure oxidative stress in semen. Oxidative stress occurs when the amount of oxygen radicals exceeds the body's ability to combat their harmful effects. Increased oxidative stress can damage the DNA of sperm.
Sperm DNA fragmentation test: A DNA fragmentation test can determine the proportion of sperm containing DNA damage. Sperm DNA damage can occur, among other things, as a result of oxidative stress. The DNA fragmentation index (DFI) describes the amount of DNA fragmentation.
If there are very few sperm or if none are produced at all, chromosomes and specific gene regions of the Y chromosome can be examined from a blood sample. These tests can identify genetic causes for weakened or absent sperm production.
A chromosome test can detect, for example, Klinefelter syndrome, where a man has an extra X chromosome (47,XXY). Klinefelter syndrome is the most common sex chromosome abnormality in men, and it is often associated with significantly weakened or absent sperm production.
The AZF regions of the Y chromosome contain genes that affect sperm formation. Deletions, or absences, in these regions can significantly weaken sperm production or completely prevent it. A Y-chromosome deletion can also be passed from father to son if a pregnancy begins with sperm carrying that deletion.
The treatment of male fertility depends on the cause affecting fertility. If a disease, hormonal disorder, medication or other treatable factor affecting sperm production can be identified, treatment is primarily targeted at that factor. Lifestyle changes can also support sperm production and fertility.
If sperm count or motility is reduced, fertilisation can be supported with fertility treatments if necessary. The form of treatment is chosen based on the quantity and quality of the sperm as well as the couple’s overall situation. Treatments can include, for example, intrauterine insemination (IUI) or in vitro fertilisation (IVF).
In more severe sperm production disorders, intracytoplasmic sperm injection (ICSI) can be used, in which an individual sperm is injected directly into an oocyte. ICSI can be used, for example, when the sperm count or motility is significantly reduced or a previous fertility treatment has been unsuccessful.
If no sperm is found in the semen, in some situations it can be searched for and collected directly from the testicle by means of a biopsy. In very severe sperm production disorders, a micro-TESE procedure can be used, where sperm is sought from testicular tissue using a microscope. If sperm is found, it can be used in micro-insemination (ICSI).
Male fertility is primarily examined with a semen analysis. In addition, laboratory tests, such as hormone tests, as well as a clinical examination and an ultrasound scan of the scrotum can be performed.
A semen analysis provides information on the count, motility and structure of sperm. In approximately 30–50% of men, impaired sperm quality is detected in connection with infertility examinations.
Fertility can be supported by avoiding smoking and intoxicants and by limiting alcohol consumption. A versatile and healthy diet, regular exercise, a suitable weight, and sufficient recovery are also important. Managing long-term stress and good treatment balance of primary diseases also contribute to supporting fertility.
A man should seek fertility examinations if pregnancy has not started after a year of regular attempts. Primary diseases or general concern about one’s own fertility are also reasons to seek examinations.
Sperm formation requires an environment for the testes that is slightly cooler than the rest of the body's temperature. Elevated testicular temperature can disrupt sperm formation and impair sperm quality.
Testicular temperature can be raised by, for example, varicoceles and being overweight. Prolonged or repeated exposure to external heat can also affect sperm production. The significance of individual heat exposures, such as taking a sauna, on fertility is likely minor.
Heat-induced changes in sperm production are usually reversible. Once the factor increasing the temperature is eliminated, sperm production can recover, but it may take about three months.
Smoking can impair sperm motility and structure as well as affect their quality. Heavy or long-term alcohol consumption can impair hormonal function and sperm production, as well as affect sperm quality. Other intoxicants can also affect hormonal function, sperm production, and sperm quality.
When trying to achieve pregnancy, quitting smoking and avoiding intoxicants support fertility. With alcohol consumption, it is advisable to keep use as minimal as possible, since heavy alcohol use can impair sperm production and quality.
