Does alfalfa have estrogen?

No, but... ...Alfalfa contains isoflavones which have a low and variable degree of estrogen like activity in animal models. One would have to consume a lot of alfalfa to have much of an effect, and there are side effects associated with this supplement which would need to be seriously considered first.
Yes, kind of. Alfalfa contains what are called "phytoestrogens, " or plant estrogens. They are found only in plants, but chemically they behave like Estrogens in a human body. But - .The majority of human estrogen is called estradiol, which is not found at all in plants.