Besides low sperm count, now they are looking at marijuana causing gynecomastia (moobs)
Janill Gilbert stashed this in Health
Not 100%, but it does offer some reproductive protection ;)
It has been rumored also that soy causes moobs:
Soybeans are a rich source of a set of molecules called "isoflavones." These substances have weak estrogen (female hormone) activity and have been used for years as "natural" remedies for hot flashes in menopausal women. Since male transgender patients take estrogens to stimulate breast growth, it has been assumed that soy might have the same effect. This appears to be a myth, or at least is not supported in the medical literature.
Neither weed nor soy does not cause moobs, or "andro-jugs" as this article refers to them.
So... Pot-smoking, tofu-eating men can expect a C cup?