This is all hypothetical, since we don't have access to the actual report referenced by the GP. However, it would be up to the CBC to support any such claim, no

This is all hypothetical, since we don't have access to the actual report referenced by the GP. However, it would be up to the CBC to support any such claim, not up to the rest of us to validate it. You could verify that the extant Chinese population does not have trouble with estrogen and soybeans. However, thousands of years is long enough for evolution to work on soybean eating populations, so I'm not convinced that would be a meaningful claim in the first place. Best case scenario, you'd find some metric for measuring historical estrogen levels in Chinese men and look as far back as possible.