Exposure to marijuana or THC (its active ingredient) produces damage to the embryo and retarded feotal growth in fish, rodents, rabbits, the rhesus monkey and humans. The most serious adverse consequences occur in the earliest stage of reproductive function on germ cells of mice and men. Decreased sperm production and abnormal forms of sperm were observed on volunteer studies in a University Hospital in 1975 – 1977. In the 70’s and 80’s, experimental studies on several animal species reported dose-related cellular damage on the testis.

The National Institute of Drug Abuse (NIDA) sponsored most of these studies that were performed by seasoned investigators and published in peer reviewed journals. NIDA, in its mandated Annual Report to Congress of 1979 and 1980 on the health hazards of marijuana, did not issue a formal warning on the subject similar to that of Surgeon General Koop of the Public Health Service who reported in a special declaration of September 1982: “That marijuana decreased sperm count and activity while interfering with ovulation and prenatal development.”During the 1990’s NIDA stopped sponsoring any additional studies on this subject, though it funded dozens of clinical controlled studies of addicts who smoked NIDA-dispensed marijuana cigarettes (and cocaine).

The protocol of these later studies did not include investigations of germ cell, sperm, or ova and did not explicitly warn the subjects on the potential risk to their reproductive function. These risks were again detailed in an international conference on ‘Marijuana and Medicine” held in 1998 at New York University Medical Center. In this conference, reports of the 70’s were validated and confirmed by current studies in molecular biology. As summarized by Professor H. Schuel who reported at the conference the presence of THC receptor sites on sperm cells:
“THC is known to affect all phases of reproduction function studies thus far in humans and laboratory animals by:
* inhibiting secretion of hormones by the pituitary gland
* affecting secretion of steroids by sexual glands
* inhibiting ovulation
* inhibiting sperm production and increasing the incidence of sperm with abnormal cells
* inhibiting the motility of ejaculated sperm
* affecting early embryonic development
* affecting implantation of the embryo into the uterine mucosa
* reducing the number of pregnancies carried to term.”

In brief, marijuana smoking puts at risk future generations before they are conceived.