When a friend of mine found out that my wife and I went vegan, he gave us a hard time about switching to soy milk. He said he would never switch from real dairy because soy milk has estrogen in it and he doesn’t want “man tits”.
Here’s the deal with that. Soy products contain phytoestrogens. These are estrogen-like hormones produced naturally by soy plants. They can either increase or decrease the amount of estrogen that is already in the human body. There is no evidence that phytoestrogens decrease fertility or cause men to exhibit the physical traits of females.
Real milk comes from pregnant cows. Giant, pregnant, female mammals that are great with child and surging with estrogen and progesterone are the only organisms in the world that produce the milk most people drink. They have been bred to produce crazy amounts of milk the whole time they are pregnant (and they are nearly always pregnant). Consequently, these hormones get passed on to the milk we drink. Butter and cheese show concentrated amounts of female cow hormones (which makes sense given that they are concentrated forms of dairy). Cow milk has been shown to increase levels of estrogen in men and even decreases their testosterone levels.
If you want something to make into a latte or a liquid medium for your breakfast cereal then you have a few choices. You can use cow milk that has real estrogen in it, soy milk that has a hormone similar in structure but not in function to estrogen, or any other milk-like alternative that has nothing to do at all with estrogen ( like rice or almond milks).