What would happen if men takes estrogen?

Quick Overview of Estrogens and Testosterones:

Estrogens are a type of steroid hormones produced by both men and women. They are the conterpart of the hormone 'testosterone' which is also present in both men and women. Estrogen hormones and testerone hormones are both sex hormones, that is they affect cells of the human body in such a way that gives each of us the characteristics of a man or a woman.

Testosterone stimulates growth of muscle mass, growth of hair (especially facial and pubic), deepens the voice, and stimulates the growth of the penis and testies in children. Men generally have around fourth to sixty times more testosterone than women do.

Estrogen stimulates the cease of vertical growth, decreases the growth of muscle mass, stimulates growth of breasts, heightens voice, etc.

A balance of both these hormones, as well as all other hormones, is necessary not only for sex related reasons but also for overall health and well-being of body and mind. These two hormones "cancel" each other out so to speak. The body produces estrogen to reverse the effects of too much testosterone and vice versa.

To More Specifically Answer Your Question:

A man who takes estrogen supplementation would experience some or all, but not limited to the following:

-Increased breast size and darker nipple color, and loss or slowed growth of body hair.

-Higher voice, reduction of "Adam's Apple", decrease in muscle mass, and generally more feminine type features.

-Decreased facial hair growth, slowed alopecia (balding or hair loss).

-Decrease in testicle size (not penis size)

-Decreased aggression and sex drive.

-Changes in personality - this is the most unpredictable of side-effects. Everyone is effected mentally in different ways. Sex hormones play a big role in mood and personality.

Very simply - a man who takes estrogen would gain more feminine features and lose some of his manly features. For the most part, testosterone is what makes men men and estrogen is what makes women women.