"Sperm concentration" refers to the amount or number of sperm cells found in a given volume of semen. It is used to measure the potency or fertility of a male in terms of sperm production. Full definition
The study did find that soy decreased sperm concentration, but did not significantly affect the sperm count itself. (nutritionfacts.org)
The participants were offered genetic testing in cases where sperm concentrations fell below 5 million / ml, and they were offered written feedback, appropriate counselling, investigation and follow - up. (sciencedaily.com)
Quick comment — the paper by Chavarro states that there was lower sperm concentration among men who consumed soy, but that the ejaculate volume was the SAME. (nutritionfacts.org)