Factors That Can Affect Male Fertility

Male fertility is a complex interplay of various physical, hormonal, and environmental factors. Disruptions in one or more of these areas can impair sperm production, quality, or function. In Germany, approximately one in six couples is involuntarily childless—in up to 50% of cases, the cause lies (at least in part) with the man. But what specific influences and diseases can limit male fertility?

1. Hormonal Disorders

Sperm production is regulated by a finely tuned hormonal balance – in particular by the interaction of:

• Testosterone
• Luteinizing hormone (LH)
• Follicle-stimulating hormone (FSH)

Diseases that disrupt this balance, such as hypogonadotropic hypogonadism syndrome, can significantly impair spermatogenesis.

2. Anatomical Changes

Structural changes or malformations of the reproductive organs can impair fertility:

• Varicocele (varicose veins in the testicles): The most common anatomical cause of male infertility. It can disrupt testicular function by increasing temperature or causing oxidative stress.
• Undescended testicles (cryptorchidism): If left untreated, this often leads to reduced sperm quality.
• Narrowing or blockages of the vas deferens—due to infections or surgery, for example—prevent the transport of sperm.
• Hypospadias: A malformation of the urethra that can impair ejaculation and thus natural conception.

3. Infections

Certain infections can directly damage the male reproductive organs:

• Mumps orchitis (testicular inflammation after mumps)
• Chlamydia or gonorrhea: Can lead to scarring or blockage of the sperm ducts.
• Prostatitis or epididymitis (inflammation of the epididymis): Acute or chronic, these can have a negative impact on sperm production.

4. Genetic Causes

Genetic disorders can severely impair fertility:

• Klinefelter syndrome (47,XXY): Often leads to greatly reduced or absent sperm production.
• Microdeletions of the Y chromosome: Small missing sections on the Y chromosome can prevent sperm production.
• Cystic fibrosis (mucoviscidosis): Often leads to missing vas deferens in men.

5. Lifestyle and Environmental Factors

External influences can also reduce sperm quality:

• Smoking, alcohol, and drug use: Damage testicular function and sperm DNA.
• Lack of important micronutrientsSperm need certain vitamins and minerals for their development:
  • Zinc, selenium, vitamin C, vitamin E, folic acid, omega-3 fatty acids→ Deficiency can lead to deformed or immobile sperm.
• Obesity: Leads to hormonal changes, especially an excess of estrogen.
• Heat exposure (e.g., from saunas, hot baths, tight clothing): A permanently elevated testicular temperature impairs sperm production.
• Environmental toxins and pollutants: Pesticides, heavy metals (e.g., lead), solvents, or plasticizers (such as BPA) have a negative effect on fertility.

6. Medications and Medical Treatments

Some medications can affect fertility as a side effect:

• Chemotherapy and radiation: Can permanently damage sperm production.
• Anabolic steroids (e.g., testosterone preparations in bodybuilding): Suppress the body’s own hormone production and can lead to azoospermia (absence of sperm).
• Antidepressants, blood pressure medication, or hormone preparations: Some of these can affect libido, ejaculation, or hormone balance.

7. Age

Unlike women, men retain their fertility for longer, but fertility also declines with age in men. From around the age of 40, the following decline:

• Sperm quality (motility, morphology)
• Hormone production
• DNA integrity of sperm

This can not only reduce the likelihood of pregnancy, but also slightly increase the risk of miscarriage and genetic abnormalities in the child.

Conclusion

Male fertility is influenced by a delicate interplay of internal and external factors. In addition to genetic and anatomical causes, lifestyle, environmental influences, and hormonal balance play a decisive role. If you are unable to conceive, you should therefore seek comprehensive diagnosis from a urologist or andrologist at an early stage—because many causes can be treated or positively influenced by a change in lifestyle.