Does Age Affect Male Fertility?

When Male Fertility Peaks, When It Declines, and the Risks of Older Fatherhood

Man holding newborn baby
Rob & Julia Campbell

Male fertility does change with age. You might get the impression that age only matters in female fertility. While the change in fertility is more drastic in women, men have biological clocks, too.

When Does Male Fertility Peak and When Does It Decline?

One research study conducted at Soroka University in Israel looked at semen quality in normal males and compared the quantity and quality of semen to the men’s ages.

The study looked at everything a semen analysis would, including how often they had sex. This is important to consider because sexual abstinence can lower semen quality. Frequent sex creates healthier sperm.

Researchers found that semen quantity peaked between the ages of 30 and 35. (Could this be nature’s way of making sure a couple conceives before female fertility starts to decline at age 35?)

On the other end of the spectrum, overall semen quantity was found to be lowest after age 55.

The Older the Man, the Weaker the Swimmers

This study also found that sperm motility changed with age. Sperm motility is how well the sperm swim.

Sperm motility was best before age 25 and lowest after age 55.

In fact, when comparing the number of “good swimming” sperm in men between the ages 30 to 35 with men over age 55, sperm motility decreased by 54 percent.

These strong variations could not be blamed on sexual abstinence, which was tracked in the study.

Increase Risk of Genetic Problems in Older Men

Besides low-quality semen, age also affects the genetic quality of male sperm.

In a study conducted at the Lawrence Livermore National Laboratory (LLNL) and the University of California at Berkeley, researchers discovered that genetic defects in the sperm increase with age in men.

These genetic sperm defects may cause:

  • decreased fertility
  • increased chance of miscarriage
  • increased risk of still birth
  • increased risk of some birth defects

The scientists reported that older men are not only at risk for infertility. They are also more likely to pass on genetic problems to their children.

A combination of female age and male age can further increase the risk of birth defects. Take for example the risk of Down syndrome.

In women, the risk of having a child with Down syndrome increases with age.

In a study of just over 3,000 children, researchers found that when a woman was age 35 or older, a man’s age mattered more.

This was especially true if the woman was age 40 or older. In this group, 50 percent of the children with Down syndrome received that genetic defect on their paternal side.

Down syndrome isn’t the only risk that increases with paternal age.

Older fathers are more likely to have children with:

  • autism
  • bipolar disorder
  • schizophrenia
  • achondroplasia, a kind of dwarfism
  • childhood leukemia

    Consider Male and Female Age Together

    It takes two to make a baby. While we can focus on the man’s age and the woman’s age, it’s also important to consider how they combine.

    A study of 782 couples investigated what the odds of conception were based on age and whether they had sex on their most fertile day (just before ovulation.)

    They found a clear decrease in fertility based on the woman’s age.

    For women aged 19 to 26, they had a 50 percent chance of getting pregnant on their own fertile day. Women age 35 to 39 had only a 29 percent chance.

    However, what’s most interesting here is the impact male age had.

    For the women age 35 to 39, if the man was five or more years older than the woman, their pregnancy success odds dropped to 15 percent.

    The odds pretty much were cut in half.

    Male Age and IVF Success

    In yet another study, this one also conducted in Israel at the Assuta Medical Center in Rishon LeZion, researchers found a link between male age and IVF success rates. They found this difference even though donor eggs were being used.

    (Donor eggs eliminate concerns of female aging problems. For women over age 40 or women with low-ovarian egg reserves, donor eggs often offer the best chance for IVF success.)

    Researchers compared the sperm and embryos of couples who IVF treatment succeeded, compared to those who have IVF treatment failure. All the couples in this study were using egg donors, so the age of the mother was not an issue.

    Until age 40, the man’s age didn’t have a big impact.

    However, when the man 40 years or older, the quality of semen went down. This may have lowered their pregnancy odds.

    Also, the embryos in the non-pregnant group were lower quality. They may also had been due to poor quality semen.

    The Bottom Line on Male Fertility and Age

    A man’s age does matter.

    Men may not have a complete drop off in fertility like women do. But “advanced paternal age” is something couples should be aware of.

    Both men and women must contend with their biological clocks.

    More on male fertility:


    Dunson DB, Colombo B, Baird DD. "Changes with age in the level and duration of fertility in the menstrual cycle.Hum Reprod. 2002 May;17(5):1399-403.

    Fisch H1, Hyun G, Golden R, Hensle TW, Olsson CA, Liberson GL. “The influence of paternal age on down syndrome.” J Urol. 2003 Jun;169(6):2275-8.

    Girsh E., Katz N., Genkin L., Girtler O., Bocker J., Bezdin S., and Barr I. “Male age influences oocyte-donor program results.” Journal of Assisted Reproduction and Genetics. April 5, 2008. [Epub ahead of print.] Accessed June 5, 2008.

    Lawrence Livermore National Laboratory (2006, June 6). Study Shows That Genetic Quality Of Sperm Deteriorates As Men Age. ScienceDaily. Retrieved June 5, 2008, from

    Lawson G1, Fletcher R2. “Delayed fatherhood.” J Fam Plann Reprod Health Care. 2014 Oct;40(4):283-8. doi: 10.1136/jfprhc-2013-100866. Epub 2014 Jun 23.

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