"To be honest with you, I would take that with a grain of salt. According to other stuff I have read, 'street drugs such as heroin, MJ, and alcohol' can cause gynecomastia in young people. Seems like another way of scaring kids. Soon you'll go blind or get hair on your palms

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"I did check the Sigma drug catalogue, the PDR, the Merck manual, and the MSDS for THC - nothing in any of them about THC causing or exacerbating gynecomastia."
"Anyway, I looked it up in my medical encyclopedia, and it states that it is usually temporary, and if a drug is the underlying cause, then the dr. should change the prescription. Have you had the problem since you started smoking, or was it before? If marijuana was the cause of your problems, I think, it would go away if you stopped.
If the problem existed before you started smoking (as it is common with puberty) then may be caused by other reasons, like liver problems or cancer. Assuming you've been checked by the doc. and cleared of those issues, it may just be a part of your chemistry, in wich case, surgery may or may not give you the desired effect.
Good Luck!"