But there is nothing to suggest this study is less reliable than any other of this kind
It was specifically (at least initially) recruiting women who believed they had been abused, not all women.
And the huge sample size surely gives some validity in itself
It is shocking that that many women came forward to say that they were abused. Sample size is important, but how representative it is is critical. This sample was generally pretty good in most categories ethnicity, religion etc. But it was recruiting women who thought they had been abused, it did not specifically try and also recruit women who had not been abused. So all of the answers are coming from a sample pool of women who have been abused. We don't know the size of that pool compared to women who have not been abused - this is where the issue lies.