Cannabis Use and Epigenetic Alterations in Human Male Sperm Cells

Inclusion Criteria: * Male gender * Between the ages of 18-40 years, inclusive; * Free from significant medical/psychiatric conditions * Willingness to provide baseline semen sample and again at the end of study participation * Willingness to comply * Ability to communicate verbally and in written form in English. For the CANNABIS USER group: * Self-reported Cannabis use of at least once weekly for past 6 months; * THC level of at least 50 ng/ml (EIA, non-creatinine adjusted value) and THCCOOH level of at least 15ng/ml (LCMSMS, non-creatinine adjusted value); * Positive result on urine rapid screening test for THC; and * Willingness to abstain from Cannabis for 11 weeks during the course of the study For the CANNABIS NON-USER group: * Self-report of no Cannabis use in the past 6 months; fewer than 10 times lifetime; * THCCOOH level = 0 ng/ml; (EIA non-creatinine adjusted value) and * Negative result on urine rapid screening test. Exclusion Criteria: * Positive result for any other drugs of abuse on urine rapid screening test (including cocaine, methamphetamine, opiates, benzodiazepines, and barbiturates); or use of nicotine or tobacco products;-Currently prescribed any psychoactive medication; * Current diagnosis of any significant psychiatric condition, including substance use disorders. For the user group, Cannabis Use Disorder that does not require immediate clinical attention in the opinion of the clinician/investigator will be allowed. * Score on the Marijuana Screening Inventory-X \> 10; * Score on the Alcohol Use Disorders Identification Test \> 8; * Expired breath CO reading of \> 8 ppm at screening and throughout the study. * Expired Breath Alcohol Level of \> 0.000 at screening. * Urinary cotinine level greater than 2- indicating urinary concentrations of \> 30ng/ml cotinine at screening and throughout the study * Estimated IQ \< 80 as assessed by the Kaufman Brief Intelligence Test, Second Edition; and * Unable to comply with study requirements or otherwise unsuitable for participation in the opinion of the study physician and/or study psychologist.