Can you please help me answer this question on turner syndrome: are alll women sterile?

Rare exceptions: 2 to 5% of xo individuals (turner syndrome) develop spontaneous menstruation, generally transient though. At least several individuals have been fertile.

Depends: Most Turner syndrome patients are a simple XO pattern, in every cell of their body and will be sterile. A few percent will be a mosaic, with some cells having a normal XX and most having XO. If the cells having XX were located in the ovary, it would be possible for them to ovulate and conceive. I have never encountered or heard of one in 4 decades, but it is possible.