These studies provided 32-200 mg/d of isoflavones and generally showed decreased midcycle plasma gonadotropins and trends … This is where the term phytoestrogen originated. Confusion about soy arises from the term "phytoestrogens." But because humans metabolize soy differently than rodents, … Soy foods do not contain estrogen. Seven soy intervention studies controlled for phase of menstrual cycle. A lot of people are convinced that the plant estrogen present in soy and other foods may increase estrogen in humans when consumed. Soy Confusion. Some soy nutrients—the isoflavones—have chemical structures that look a bit like the estrogen found in a woman's body. New studies suggest that eating large amounts of soy’s estrogen-mimicking compounds might reduce fertility in women, trigger early puberty and disrupt development of fetuses and children The researchers particularly compared infants fed with soy … The current study investigated the postnatal development of estrogen-responsive tissues, along with specific hormone levels, according to infant feeding practices. A new study is challenging that. However, phytoestrogens are not the same thing as female estrogens. Most studies linking soy consumption to an increased risk for breast and other forms of cancer are done in laboratory animals.