Male fertility involves a man’s ability to produce and deliver healthy sperm capable of fertilizing an egg. Sperm are produced in the testes, and their quality is assessed based on concentration, motility, and morphology. Motility refers to the sperm’s ability to move effectively, while morphology describes the sperm’s shape and structure. A normal sperm concentration typically ranges from 15 million to over 200 million sperm per milliliter of semen.
No Definitive End to Male Fertility
Men do not experience a complete cessation of fertility at a specific age, unlike women who undergo menopause. Sperm production generally continues throughout a man’s life, even into his 60s, 70s, or beyond. While the ability to produce sperm persists, its quality and quantity can change over time.
Age-Related Changes in Male Fertility
Male fertility undergoes changes with advancing age. Sperm quality often declines, characterized by increased DNA fragmentation, reduced motility, and abnormal morphology. Sperm DNA damage tends to increase with age, with men over 50 more likely to show fragmentation than younger men.
Sperm motility consistently decreases with age, affecting how well sperm can reach and penetrate an egg, with a significant drop often occurring for men over 40. The shape of sperm can also be affected, with an increase in abnormally shaped sperm over time. While sperm concentration might not drastically decline until later years, the cumulative effect of decreased motility and morphology can reduce the chances of successful fertilization. Hormonal changes also play a role, as testosterone levels naturally decline after age 30, impacting sperm production and overall reproductive health.
Factors Influencing Male Reproductive Health
Beyond chronological age, various lifestyle and health factors affect male reproductive health. Diet and exercise habits contribute to overall well-being, supporting sperm quality. Habits such as smoking, excessive alcohol consumption, and illicit drug use can negatively impact sperm count, motility, morphology, and DNA integrity. Cigarette smoking, for example, is associated with lower sperm counts, reduced motility, and DNA damage.
Obesity is a factor that can impair male fertility by reducing sperm count, movement, and quality. Chronic health conditions like diabetes and hypertension, and certain medications, can also affect reproductive function. Environmental toxins and excessive heat can further compromise sperm production and quality. Managing these factors can help mitigate potential adverse effects on fertility.
Implications of Advanced Paternal Age
While men can father children later in life, advanced paternal age is associated with certain considerations for the offspring. There is an increased, though generally small, risk of genetic mutations in children born to older fathers. These mutations can lead to a higher chance of certain genetic disorders, such as achondroplasia. Advanced paternal age has also been linked to an increased risk of neurodevelopmental conditions, including autism spectrum disorder and schizophrenia. Men aged 45 or older may have children with an increased risk of early-onset schizophrenia.
Advanced paternal age can also impact pregnancy outcomes for the partner, with associations to higher risks of miscarriage, preterm birth, and low birth weight. It has also been linked to an increased likelihood of the mother developing gestational diabetes. These risks are typically low but are important considerations for couples planning a family at an older paternal age.