How healthy is your sperm, based on the data?

4% normal morphology is the WHO 2021 reference limit. Strict (Tygerberg/Kruger) morphology assessment is extremely rigorous: even the median is only about 11%. A result at or above 4% is within reference range. Below 4% is associated with reduced fertility but does not make conception impossible.

A landmark meta-analysis by Levine et al. (2017), covering 42,935 men, found that sperm concentration in Western countries declined by approximately 52% between 1973 and 2011. An updated analysis (Levine et al., 2022) showed the decline is accelerating and now global. Proposed causes include endocrine-disrupting chemicals, obesity, heat exposure, and lifestyle changes.

Seek medical evaluation if you and your partner have been trying to conceive for 12 months without success (6 months if the female partner is over 35). Also consult a doctor if you notice blood in semen, unusual colour, very low volume, have a history of testicular injury or surgery, or have been treated for cancer.

The WHO 2021 lower reference limit for sperm concentration is 16 million per millilitre, and for total sperm count per ejaculate it is 39 million. These are 5th percentile values: 95% of fertile men in the reference studies had values above these numbers. The median sperm concentration is approximately 73 million per mL, so "normal" covers a very wide range. A count below the reference limit does not mean infertility; it means further evaluation is recommended. Many men with lower counts conceive naturally. (Sources: WHO, 2021; Campbell et al., 2024.)

Yes, though the decline is more gradual than for female fertility. Studies show sperm volume, motility, and morphology tend to decrease after age 40. Sperm concentration may remain relatively stable, but DNA fragmentation increases with age. A meta-analysis by Johnson et al. (2015) found men over 40 had significantly higher rates of DNA damage. Paternal age is also associated with slightly increased risks of certain conditions in offspring. However, men can remain fertile well into their 60s and beyond. The decline is a gradient, not a cliff. (Sources: WHO, 2021; Johnson et al., Ageing Research Reviews, 2015.)

Evidence-based strategies include: maintaining a healthy weight (obesity is associated with lower count and motility), avoiding excessive heat exposure (hot baths, laptops on lap, tight underwear), stopping smoking (associated with 23% lower concentration per Sharma et al., 2016), limiting alcohol to moderate levels, exercising regularly but avoiding overtraining, and eating a diet rich in antioxidants (vitamins C and E, zinc, selenium, folate). A full semen turnover cycle takes approximately 74 days, so improvements may take 2-3 months to appear in a semen analysis. (Sources: Sharma et al., Reproductive Biology and Endocrinology, 2016.)

Total motility includes all moving sperm, whether swimming forward, in circles, or just twitching in place. Progressive motility counts only sperm swimming in a forward direction or large circles, which is the movement needed to reach and fertilise an egg. The WHO 2021 reference limits are 42% for total motility and 30% for progressive motility. Progressive motility is considered more clinically relevant for predicting fertility. A man could have 42% total motility but only 20% progressive motility if many sperm are moving non-progressively. (Sources: WHO, 2021.)

FDA-cleared home sperm tests such as YO Sperm Test and ExSeed measure concentration and, in some cases, motility. Studies show they correlate reasonably well with laboratory results for concentration, with accuracy rates of approximately 95-97% for detecting whether count is above or below a threshold. However, they do not assess morphology, DNA fragmentation, vitality, or other parameters included in a full semen analysis. Home tests are useful as a screening tool but should not replace a clinical evaluation if results are concerning or if conception has not occurred after 12 months. (Sources: YO clinical validation studies; ExSeed peer-reviewed data.)