Eating even moderate amounts of soy can cut a man's sperm concentration in half, because foods like tofu and soy milk contain estrogen. And two hormone-like compounds linked to the consumption of soy-based foods can cause irreversible changes in the structure of the brain, resulting in early-onset puberty.
Researcher Jorge Chavarro says...
A lot of women are taking soy supplements to help with the symptoms of menopause, because it contains a vegetable form of estrogen. However, new tests show it can reduce normal sexual behavior as much as 70%. Women may accept the end of fertility, but few want this to include the end of their sex lives as well.