Pot does not increase your body's production of estrogen. Rather it itself is mildly estrogenic. Either delta-9-thc or one of its cannabinoid metabolites does indeed have some estrogenic activity.
As far as the dank decreasing test levels, there really is no definative awnser, go ahead and search medline, you'll find a 50/50 ratio of studies each saying the opposite of the other. Personally I feel this effect is highly individual. I have definately seen cases of chronic smokers who some seriously low free-test levels.
Whatever you decide, please use a waterpipe, bong, vaporizer, or something else which cools down the smoke and filters out some of the tar. Research has yet to prove pot to cause lung cancer, but the lungs obviously were not designed to inhale combustible organic material.