A recent study indicates that male infertility is often underreported, with many men not getting tested for sperm quality. According to a 2026 review published in the journal Antioxidants, global sperm counts have fallen by more than 51% since 1973, with an accelerating decline. Edidiong Akang, a reproductive biologist at the University of Lagos, Nigeria, stated, "Male infertility is understated. It is so huge a problem."
In a study led by Akang and published in the journal Scientific Reports in 2023, researchers analyzed semen samples from over 17,000 men and found that sperm morphology had deteriorated by about 50% between 2010 and 2019. Sperm motility also declined significantly, with a reported drop of 87% in Nigeria during the same period. Akang noted that the male share of infertility is "grossly underreported" and often misunderstood.
Factors affecting male fertility include sperm shape, size, motility, concentration, and count. These factors can be influenced by underlying health conditions such as weight gain, stress, poor sleep, smoking, microplastics, and cannabis use. Weight gain can raise the temperature of the testes, which negatively impacts sperm production.
Men under 40 years old typically do not have regular check-ups for fertility, unlike women who have monthly menstrual cycles that may indicate reproductive health issues. Riffat Bibi, a clinical embryologist in Pakistan, noted that many men often suggest checking their partner first, reflecting a misconception that sexual activity equates to fertility.
Bibi reported that around 80% of her cases now involve male factors, a significant increase from the previously assumed 50-50 split. This trend is also evident in IVF treatments, where poor sperm quality necessitates the use of advanced techniques to achieve fertilization.
An additional concern is the use of anabolic steroids, which can suppress sperm production. Harrison Pope, a researcher at Harvard Medical School, explained that while steroids enhance athletic performance, they can lead to reduced fertility due to an excess of testosterone. Recovery of sperm production is possible upon cessation of steroid use, but outcomes vary based on duration and dosage.
Chirag Bhandari, who runs the Institute of Andrology and Sexual Health in India, estimates that steroid use accounts for less than 0.1% of declining sperm counts in the country, with overweight, heat stress, and smoking being more significant contributors. Early testing can often restore sperm counts to normal within six to twelve months, but delays in detection can reduce the likelihood of recovery.