Last updated on: 5/30/2008 | Author:

Can Marijuana Use Harm Fertility?

General Reference (not clearly pro or con)

Alison Murdoch, MD, Head of the Department of Reproductive Medicine at Newcastle Fertility Center, was quoted in an Oct. 13, 2003 BBC article:

Male fertility is quite complicated. The partners of men with low sperm counts can sometimes achieve pregnancy, and it is only when men produce very, very small amounts of sperm that they can be considered infertile.’

Oct. 13, 2003

PRO (yes)


Haibin Wang, PhD, Research Assistant Professor at Vanderbilt University Medical Center, and Huirong Xie, PhD, a Postdoctoral Fellow in the Department Of Cell And Developmental Biology at Vanderbilt University Medical Center, et al., wrote in their 2006 study of mice, “Fatty Acid Amide Hydrolase Deficiency Limits Early Pregnancy Events,” published in the Journal of Clinical Investigation:

Exposure to Delta-9-THC [one of the active ingredients in marijuana] causes retarded development and oviductal retention of embryos…

We speculated that these developmentally retarded embryos eventually fail to implant in the uterus… When examined on day 5, most of the mice (7 or 8) exposed to THC failed to show any sign of implantation…

These findings reinforce the idea that during normal pregnancy, locally produced endocannabinoids elicit an ‘endocannabinoid tone’ conductive to synchronous development and timely journey of embryos through the oviduct for on-time implantation, whereas an exposure to exogenous cannabinoid [that which enters from outside the body] ligands such as THC swamps this endocannabinoid tone, leading to early pregnancy failure.



Charles Ksir, PhD, Professor of Psychology at the University of Wyoming, and Oakley Ray, PhD, Emeritus Professor of Psychology and Pharmacology at Vanderbilt University, wrote in their 2004 textbook Drugs, Society and Human Behavior:

Heavy marijuana smoking can decrease testosterone levels in men, although the levels are still within the normal range and the significance of those decreases in not known.

There have been reports of diminished sperm counts and abnormal sperm structure in heavy marijuana users, but again the clinical significance of these reports is not clear.



Lani J. Burkman, PhD, Assistant Professor of Gynecology and Obstetrics at the University of Buffalo, et al., presented a study at the annual meeting of the American Society of Reproductive Medicine in San Antonio on Oct. 13, 2003, which found, as reported by WebMD:

When women smoke marijuana, the active ingredient — THC — appears in their reproductive organs and vaginal fluids. Sperm exposed to this THC are likely to act just as sperm exposed to THC in the testes.

When women smoke marijuana, nicotine, or other drugs, their reproductive fluids contain these drugs.

The woman smoking marijuana is putting THC into her oviduct, into her cervix. If the man is not smoking but the woman is, his sperm go into her body and hit THC in the vagina, oviduct, and uterus. Her THC is changing his sperm.

Oct. 13, 2003


Herbert Schuel, PhD, Professor Emeritus of Anatomy and Cell Biology at the University of Buffalo, and Lani Burkman, PhD, Assistant Professor of Gynecology and Obstetrics at the University of Buffalo, et al., presented their study at the 2003 annual meeting of the American Society of Reproductive Medicine, stating:

Marijuana smokers appear to have impaired fertility potential.

Smoking men have reduced semen volume and total sperm number. Seminal sperm from MJ men express abnormally high hyperactivated mobility which persists after a wash and swim-up. These sperm may burn out quickly and reduce fertility.

We note that women smoking marijuana will have elevated THC throughout their reproductive tract, thus affecting sperm in the cervix, uterus and oviduct.



Herbert Schuel, PhD, Professor Emeritus of Anatomy and Cell Biology, who presented his research into marijuana’s effect on reproduction at the annual meeting of the American Society for Cell Biology, stated in a Dec. 12, 2000 BBC News article:

“We know that sperm capacitation and fertilising potential are tightly regulated within the female reproductive tract.

Within the uterus, anandamide [a naturally occurring endogenous cannabinoid neurotransmitter found in the brain, which is sensitive to the cannabinoids in marijuana] regulates early development of the fertilised egg, and determines where the embryo will implant to initiate pregnancy. Cannabinoids also affect this process…

The increased load of cannabinoids in people who abuse marijuana could flood natural endocannabinoid-signal systems in reproductive organs and adversely impact fertility.”

Dec. 12, 2000


Sheena Lewis, PhD, Professor and Director of the Reproductive Medicine Research Group at the Queen’s University, directed a study which was covered in a Mar. 31, 2004 article by BBC News:

The study … examined the direct effects on sperm function of THC, the active ingredient in cannabis. The group found that THC made sperm less likely to reach the egg to fertilise it.

They also discovered that the presence of cannabis impaired another crucial function of sperm – the ability to digest the egg’s protective coat with enzymes to aid its penetration.

Mar. 31, 2004

CON (no)


The National Organization for the Reform of Marijuana Laws (NORML) stated on its website (accessed Mar. 17, 2006):

Government experts concede that pot has no permanent effect on the male or female reproductive systems…

A couple of lab studies indicated that very heavy marijuana smoking might lower sperm counts.  However, surveys of chronic smokers have turned up no indication of infertility or other abnormalities.

Mar. 17, 2006


John Oxford, MD, Professor of Virology at the Queen Mary School of Medicine and Dentistry, University of London, stated in a Nov. 25, 2003 BBC News article:

“We know that cannabinoids affect sperm – although there’s not much objective evidence that it has an effect on female fertility.

It’s difficult to carry out a proper controlled trial to find out what is happening.”

Nov. 25, 2003