In an excellent but out-of-print book, Stepping Stones to Labor Ward Diagnosis, I read how to determine the obstetric type without doing an internal exam. The author was a practicing obstetrician/gynecologist in Australia in the 1950s and into the 1970s. During that time a link was found between bone cancer in pre-adolescent males and routine x-ray for fetal position, size and pelvic compatibility during the ninth month gestation. (Does this sound familiar for ultrasound exam today?) Further studies on x-ray exposure during pregnancy showed other links to fetal anomalies and led to warnings against such exposure.