becomingoverweight:
Well fat is feminizing. The more fat you have, the more aromatase you have. The more aromatase you have, the more of your androgens get converted into estrogen.
boundandfeed:
Yes, but how much fat would you have to have, for the estrogen to stop erections and shrink the boys?
Small amounts can be used as a contraceptive, but 6 or more months would almost invariably have a permanent effect.
You should speak to a health professional before taking anything hormonal, there are a lot of factors to consider and I can only speak of my personal experience with HRT, which WILL differ.