This ship has sailed. Soy actually  protects against breast cancer per this review by Dr. Greger.

There are numerous studies refuting this knee jerk reaction  that stems from a half-truth. Yes, soy is a phytoestrogen. That does not mean it acts like estrogen in breast tissue. In fact, it blocks it. This is another great discussion by Dr. Greger discussing how soy acts differently in bone vs the breast, and another discussion in this blog.

Here are a few  studies that showed drops in breast cancer deaths from 12% to 25% with higher soy protein, even just one cup a day:

• This 2019 study of 330,000 participants showed at least a 12% drop in breast cancer deaths for each 5 gm/day increment of soy protein (that's <1/6th cup of soybeans)
• This 2009 study of 1600 women showed if consumed consistently during childhood, soy consumption may cut the risk of breast cancer later in life by half. Women who consume soy primarily as an adult reduce their breast cancer risk by 25%.  For women with breast cancer, just a single cup of soy milk may reduce the risk of recurrence by 25%.  
• This study of  11,000 women saw  a 15% reduced breast cancer death rate, and a 21% reduced risk of recurrence.
• This 2022 study , a meta-analysis (review of many other studies) of soy and breast cancer risk showed reduced risk for both pre and post menopausal women.

Here is the opinion published by the American Cancer Society. "So far, the evidence does not point to any dangers from eating soy in people, and the health benefits appear to outweigh any potential risk. In fact, there is growing evidence that eating traditional soy foods such as tofu, tempeh, edamame, miso, and soymilk may lower the risk of breast cancer, especially among Asian women. Soy foods are excellent sources of protein, especially when they replace other, less healthy foods such as animal fats and red or processed meats.

‍