UroToday ("Breaking Urology News written by Urologists for Urologists") is reporting a study in the journal Fertility and Sterility that finds that eating soy products might affect semen quality. To wit:
There was an inverse association between soy food intake and sperm concentration that remained significant when evaluated with respect to age, abstinence, body mass, and caffeine, each of tobacco intake. There was no impact on sperm motility of morphology.
Access the UroToday report of the study here.