This is a silly meme. Plants contain phytoestrogen, which is not the same thing as estrogen. Ingestion of phytoestrogen actually seems to reduce the body's own natural estrogen production, which has the effect of reducing female fertility. Eating soy does not turn men into women, despite what insecure dudes on the internet may have told you. (Amusingly, despite all the hand-wringing about soy, I have never seen a similar campaign to decry milk, which actually does contain estrogen (although inert)).

Also, if soy did feminise the human body, transfeminine people would recommend eating nothing but soy to each other.

We do that, but we're joking.

I have always struggled to square this reality with the common recommendation from oncologists for women at high risk of breast cancer to eat less soy. Would a reduction in the bodies estrogen production increase the risk of breast cancer?

Two of the most ripped and jacked dudes I know are vegetarian or vegan. If you can't bulk on soy you should try lifting more bro.

This is common social media bro science but show me the human outcome data that corroborates this.

Do you have sources for that?

As I understand that was meat industry propaganda that found a new life on the internet. Early veggie burgers were made out of soybeans so the industry made up the "soy turns you into a woman" meme to discourage people from switching. Then it got picked up by conspiracy nuts and got amplified way past the original market.

Here you go.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7468963/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270274/