The research in this area is (complicated) by the fact that infertile women appear to be at higher risk for ovarian cancer to begin with, which is why this study (compared) infertile women with one another rather than with other women in the (population). In addition, because ovarian cancer is quite rare, large populations must be studied to obtain (meaningful) results. The scientists (cautioned) that the women in the study would have to be followed for many more years to see if their risk increased over time. The mean age for (diagnosis) of ovarian cancer in women is 63.
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