Testosterone levels not affected by soy protein

For a long time people, particularly males, have been under the impression that using soy as a protein source would lower testosterone levels and cause feminising side effects.
Much of this has never been proven and probably often a way for people to justify eating more meat.
Recently a study has been published proving there is no correlation between soy protein supplementation and diminishing testosterone levels in males, demonstrating that soy may be a great addition to a musclebuilding diet.
The study done by Hamilton-Reeves, et al., at St. Catherine University and the University of Minnesota was set to determine the effects of the active constituents of soy (mainly isoflavones) on estrogen levels in males.
A total of 47 research reports covering a total of 51 groups was analysed and was reviewed by independent groups and showed no effect on testosterone, estrogen, free testosterone and SHBG (sex hormone binding globulin - which effects free testosterone) by soy products.
This study can allow people to rest easy and to possibly add some more soy into their diets.