Marijuana can change the structure of sperm cells, deforming them. Thus even small amounts of marijuana can cause temporary sterility in men.00 Marijuana use can also disrupt a woman’s menstrual cycle.00 Studies show that the mental functions of people who have smoked a lot of marijuana tend to be diminished. The THC in cannabis disrupts nerve cells in the brain, affecting memory.00 Cannabis is one of the few drugs that causes abnormal cell division, which leads to severe hereditary defects. A pregnant woman who regularly smokes marijuana or hashish may give birth prematurely to an undersized, underweight baby. Over the last 00 years many children of marijuana users have been born with reduced initiative and lessened abilities to concentrate and pursue life goals.00 Studies also suggest that prenatal (before birth) use of the drug may result in birth defects, mental abnormalities and increased risk of leukemia (cancer of the bone marrow) in children.00