Testicular atrophy is one such issue, although many of the studies suggesting it does cause shrinkage are relatively outdated — from the 1980s. Nevertheless, the majority of it suggests that smoking weed lowers testosterone levels, either directly or through precursor hormones; or causes testicular atrophy in monkeys and dogs. A study from 2012 revives this idea, and finds some evidence in men living in the Niger delta area of Nigeria. In that study, 75 men who smoked marijuana were also likely to have shrunken testicles, infertility, and even male breasts.
Under the pseudonym “Mr. X,” Sagan wrote a 1969 essay for Time magazine about the personal benefits he’d seen from cannabis use . Then in his mid-30s, he admitted to smoking throughout the prior decade. “I find that today a single joint is enough to get me high,” he wrote , going on to observe that marijuana had enhanced his appreciation for art and music. He concluded that “the illegality of cannabis is outrageous, an impediment to full utilization of a drug which helps produce the serenity and insight, sensitivity and fellowship so desperately needed in this increasingly mad and dangerous world.”