It's a proven cause. Medical uses are sometimes very beneficial. The key point is that women can receive all the benefits of medical radiation with vastly LESS HARM, if the medical professions will reduce unnecessarily high dose-levels and frequencies of exposure. The story of a Major, Proven, Preventable Cause of This Disease. The extra hazard is more severe for the child.
Every exposure adds to a population's rate of cancer.
Even small reductions in average dosage can produce large benefits in prevention of cancer.