A risk factor is something that raises the chances of getting a health problem. A person can become infertile with or without the ones listed below. The chances of becoming infertile are greater in people who have many. Things that can raise the risk are:

Tobacco, Marijuana, Illegal Drugs, and Excess Alcohol

Tobacco products can reduce sperm count, make it harder for them to move, and increase the number of abnormal sperm. Marijuana and illegal drugs can also cause harm.

Excess alcohol can affect hormone levels and lower sperm count and quality.

Infections

Some infections can cause blockages or scarring in the tubes that carry sperm. Others can cause swelling of the testes. These problems can affect sperm count and quality. Some infections that may cause problems are:

• Sexually transmitted infections (STIs), such as gonorrhea and chlamydia
• Viral infections, such as mumps and prostatitis
• Bacterial infections, such as tuberculosis

Trauma

The testicles can be harmed during sporting events or fights. This can cause swelling and lower blood supply to the testicles. It can lead to lasting damage to cells that make sperm.

Surgeries

Some surgeries may lead to infertility. This includes surgery of the prostate, pelvis, or bladder and procedures like hernia repair or orchiopexy.

Radiation, Toxic Chemicals, and Heavy Metals

Radiation therapy and radiation exposure can both lower sperm count and testosterone levels.

Workplace and environmental chemicals and heavy metals have also been linked to male infertility. They are thought to cause problems with hormone function.

Exposure to Excessive Heat

Excess heat can lower sperm count and quality. Some sources are:

• Saunas and hot tubs
• Laptop computers
• Tight underwear and clothing
• Riding a bicycle

Some bicycle seats may also cause problems with blood flow and nerves in the groin. This can cause problems with erection.

Obesity

Obesity can lower sperm count and hormones.

Medications

Certain medicines, such as alpha and beta blockers, anabolic steroids, and diuretics can lead to infertility.

Health Problems

Some health problems that may lead to infertility are:

• Blockages in the genital tract from things like cysts and abnormal structures can make it hard for sperm travel
• Diseases like diabetes, high blood pressure, cirrhosis, and multiple sclerosis can make it hard for the testes to make testosterone
• Hypothyroidism—low amounts of thyroid hormones can cause problems with sperm count and quality
• Problems with ejaculation, such as spinal cord injury
• Pituitary tumors can make it hard for the body to make the hormones needed to make sperm

Genetic Problems and Birth Defects

Cystic Fibrosis

Cystic fibrosis is an inherited disease that causes the body to make thick and sticky mucus. Men with cystic fibrosis do not have a sperm canal.

Chromosome Disorders

Chromosome disorders like Klinefelter syndrome can cause problems with cell division or with how the testes develop.

Birth Defects

Some men are born with problems with their reproductive organs, such as problems with the tubes that carry sperm or testicles that do not descend as they should.