Would you say the same to a 25 year old who had already been diagnosed with breast cancer? Somehow I doubt it.
There is no question that elevated estrogen levels are a cancer risk. That is why a first pregnancy ending in abortion increases your risk of breast cancer, for example. (Also a first pregnancy ending in miscarriage). Certain hormone levels rise, but the others who counteract them don’t come, so they increase the risk of cancer.
Obviously I am not a doctor! Duh, but you can’t mess around with peoples’ hormones and not affect them negatively.
Yes, if she wasn’t married when she got pregnant.