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“Some of these can be reversed, but others can have long-lasting effects, such as certain types of chemotherapy that are toxic to the male reproductive system,” he says. “We have seen that even environmental factors, ubiquitous in western countries, can penetrate the testicles and semen and affect fertility in men.” 

The effects of a man’s age��

“We know that there’s an age-related decline in testicular function as men age,” says Dr. Kashanian. “This includes as much as a 1 percent decline in testosterone levels per year, starting sometime during a man’s 40s.����

“We also see a decline in various semen parameters as men age,” he continues. “These include semen volume, along with sperm motility (the ability of sperm to move) and morphology (the size, shape and appearance of sperm). We also see increased sperm aneuploidy—one or more extra or missing chromosomes in sperm cells—in advanced paternal age.” This last abnormality may be caused by aging-related chronic conditions, such as diabetes and vascular disease, which erode the body’s ability to repair itself and may lead to a decrease in male hormone levels.��

How does advanced paternal age affect a man’s offspring?��

“W�� have��’t been able to specify what qualifies as advanced paternal age—at least not yet—but many of us in the field would estimate it to be between 40 to 50 years old. Beyond that, there is a significant increase in risk for men in their seventh a�Ի� eighth decades of life, especially for their offspring. ��

The children of older fathers are at greater risk for autism spectrum disorders, schizophrenia, ADHD, cardiovascular problems and rare genetic diseases.   

Getting tested for infertility��

The best way to assess male fertility is through semen analysis. That alone will not fully predict a man’s ability to conceive, but it will provide a rough evaluation of a man’s semen and sperm, Dr. Kashanian says. “A lot can be learned from semen analysis, and if abnormalities are present, further evaluation is warranted.” ��

Many factors can affect a male’s fertility. However, varicoceles—enlarged veins in the scrotum—are the most common cause of infertility. These are present in 20 percent of men. Although they do��’t always cause infertility, they are easily treatable with surgery.��

Another major cause of infertility is azoospermia (the absence of sperm in the ejaculate). Azoospermia can be obstructive (caused by a blockage) or non-obstructive (caused by poor sperm production). ��

Blockages may originate with a vasectomy, infection, pelvic surgery or a prostate cyst. They may also be congenital—something you’re born with—such as the lack of a vas deferens, the duct that transports sperm out of the testes.��

“Roughly 1 percent of men have non-obstructive azoospermia, possibly caused by genetic abnormalities, medications or a variety of medical conditions,” he says.��

“W�� can often distinguish between obstructive vs. non-obstructive azoospermia via a thorough physical exam and laboratory tests. In either case, surgery is required to extract sperm from the testicle or epididymis (another part of the male reproductive system where sperm are stored). The extracted sperm can be used later for in vitro fertilization (IVF).��

A common genetic cause of infertility in men��

Here’s a quick review of human genetics and gender.��

All of us have 46 chromosomes. Males have one X chromosome and one Y chromosome, while females have two X chromosomes. The Y chromosome carries the genes that are responsible for producing sperm.��

Some men may have an extra X chromosome, or XXY. �ճ󲹳�’s called Klinefelter syndrome, and it occurs in approximately 1 in 500 males. ��

Children and adults with Klinefelter syndrome may not have obvious physical differences, Dr. Kashanian explains. “There may be growth or developmental concerns in early childhood, best dealt with by specialists in endocrinology, developmental/behavioral pediatrics or speech/language therapy. The majority of men with this abnormality will have azoospermia. At �鶹����, we have a multi-disciplinary Klinefelter Syndrome Care Center for children and adults with Klinefelter syndrome.”��

If you suspect you are infertile, see your doctor for a referral to an infertility specialist. There are tests that may tell if you have fertility problems. When it’s possible to find the cause, treatments may include medications, surgery or  . Happily, many couples treated for infertility are able to have babies, Dr. Kashanian says.��

Look for part 2 in this series, which will focus on male sexual health.��