Soybeans (and some other things, like flax seeds) contain phytoestrogens, which are estrogen-like compounds. They are somewhat controversial, since they may weakly bind to estrogen receptors, which may either cause greater estrogen-like activity (by having more things attached to the estrogen receptors) or lesser estrogen-like activity (by displacing real estrogen on the estrogen receptors). Unless soybeans and flax seeds are a huge proportion of your diet, it is probably not a huge difference overall.