Gynecomastia.org is beginning a list of drugs that have gynecomastia as a potential side effect. This is just a beginning and with your help it will continue to grow.
Another source of infomation. Adverse Reactions.
For a more extensive list go here.
Here are links for adiapose tissue conversion of testosterone to estrogen. Here are a couple, though probably not the best. The second only mentions aromatase in females, but as the first notes, this happens in males as well. We will be happy to post other information as we find it or as it is sent to us.
A different view: (Excerpt from paper on cause of Gynecomastia)
From this information it was discovered that there is also a lower ratio of weaker adrenal androgens (delta 4-androstenedione and dehydroepiandrosterone) found in youths with this disease. It was once believed that there was an imbalance in the ratios of testosterone to estrogen or estradiol, but this is now know to be untrue.
Interesting reading here, especially the estrogen like qualities of the everyday food we eat.