New research shows that marijuana causes genetic changes in sperm, although it is unclear what the effect of those changes is or whether it is passed on to the children of men.
But scientists said their findings suggest that men who try to have children should think about avoiding marijuana.
In experiments with rats and a study of 24 men, the team at Duke University discovered that tetrahydrocannabinol (THC), the psychoactive component of marijuana, affects genes in two major cellular pathways and alters DNA, a necessary process for natural development.
“What we have discovered is that the effects of cannabis abuse on men and their reproductive health are not completely nullified,” said Scott Collins, lead author of the study. “There is something about cannabis that affects the genetic image in sperm.” He is a professor of psychiatry and behavioral science at Duke.
“We still do not know what that means, but we must think about the fact that more young people of reproductive age have the legal right to use cannabis,” Collins said in a news release.
For the study, the researchers compared men who had been using marijuana regularly (at least weekly for the previous six months) with men who had not used marijuana in the past six months and did not exceed 10 times in their lives.
The researchers found that the higher the concentration of tetrahydrocannabinol in urine in men, the greater the genetic changes in their sperm.
Susan Murphy is Director of Reproductive Science in Obstetrics and Gynecology at Duke. THC seems to affect hundreds of different genes, but many are linked to two of the same major cellular pathways, he said.
One track plays a role in full-size devices, while the other co-organizes growth during development. He pointed out that both routes can be interrupted in some types of cancer.
“As for what it means for a developing child, we do not know,” said Murphy.
She said that it was not even known if the sperm infected with the substance could be healthy enough to fertilize the egg and continue to grow into a fetus.
The researchers plan to study larger groups of men to see if any genetic changes, if any, are transferred to the changing sperm in the THC of the children and if these genetic changes are modified in the sperm if the man stops using marijuana.
“In the absence of a more comprehensive and definitive study, the best advice would be to assume that these changes will be there,” said Murphy. I do not know if they will be permanent, I would say that, as a precaution, stop using cannabis for at least six months before trying to conceive. “