study conducted in 2005; n=35; p-values vary based on measurements; study conclusion is "[...] soy protein, regardless of isoflavone content, decreased DHT and DHT/testosterone with minor effects on other hormones, providing evidence for some effects of soy protein on hormones."; further study on larger/more diverse populations required.

Read study entirely and in context before judging effect size based on study alone but the data indicates further study is worth pursuing.