Ann, that's exactly my point.  In my experience, almost all autosomal matches reported by the One-to-Many tool for females, using the default criteria and for segment lengths greater than 10 cM, can be confirmed by the One-to-One (autosomal) comparison tool.  On the other hand, the vast majority of X matches for females, again using the default criteria and for segment lengths greater than 10 cM, are NOT confirmed by the X One-to-One comparison tool.  The discrepancy is extreme, something like 90 percent or more confirmable for autosomal matches, versus something like 1 percent confirmable for X matches.  Phasing has something to do with it, but I'm fairly sure phasing does not eliminate 90 percent of female autosomal matches reported by the One-to-Many tool!  Hence I suspect that the X matching algorithm used by the One-to-Many tool is doing something different from the algorithm used for autosomal matching in the same tool.   John McCoy ([email protected])   In a message dated 10/9/2017 2:42:18 AM Pacific Standard Time, [email protected] writes:   I agree that phasing reduces the number of matches enormously, for the autosomes as well as the X in females. I did think the length of the segment reported by Wesley should have been long enough to show up in the one-to-one. Ann Turner