Parasite Infecting Up to 50% of People Can Decapitate Human Sperm

> A recent study found that male infertility rates increased nearly 80% from 1990 to 2019. The reasons driving this trend remain a mystery, but frequently cited culprits include obesity, poor diet and environmental toxins.

> Infectious diseases such as gonorrhea or chlamydia are often overlooked factors that affect fertility in men. Accumulating evidence suggests that a common single-celled parasite called **Toxoplasma gondii** may also be a contributor. An April 2025 study showed for the first time that “human sperm lose their heads upon direct contact” with the parasite.

> Infected cats defecate Toxoplasma eggs into the litter box, garden or other places in the environment where they can be picked up by humans or other animals. **Water, shellfish and unwashed fruits and vegetables** can also harbor infectious parasite eggs. In addition to eggs, tissue cysts present in the meat of warm-blooded animals can spread toxoplasmosis as well if they are not destroyed by cooking to proper temperature.

> Toxoplasma remains in the body for life as dormant cysts in brain, heart and muscle tissue. These cysts can **reactivate** and cause additional episodes of severe illness that **damage critical organ systems.**

> Between **30% and 50% of the world’s population is permanently infected** with Toxoplasma due to the many ways the parasite can spread.

Oh no, not my sperm!

Wait I don’t have any of those any more. Whewf. Dodged a bullet there..

Tinfoil hat time: maybe this parasite co-evolved with cats to reduce the number of offspring the people had so they could devote more resources to their cats.