Schistosomiasis (bilharziasis) is a major human disease caused by three species of the genus Schistosoma, known collectively as blood flukes. Africa and western Asia (e.g., Iran, Iraq) are endemic centres for S. haematobium; S. mansoni also is found in these areas, as well as inâ¦
How Alcohol Damages Sperm. Alcohol can reduce the quantity of sperm a man produces (his sperm count) and the quality of that sperm. One way in which alcohol does this is by preventing the body from absorbing zinc in the normal way. Zinc is found in high quantities in sperm.
Marijuana use may affect the size and shape of men's sperm. Smoking marijuana may affect the shape and quality of young menâs sperm, ultimately putting their fertility at risk, new research shows. In a study published in the medical journal Human Reproduction, researchers analyzed many different lifestyle factors that could possibly have an impact on male infertility.