If you and your match are both men there is a special opportunity for one-to-one confirmation if you match either on your X chromosomes. Since men have only one X chromosome, no triangulation is necessary"
I did yesterday but somehow it didn't get posted.
What I think I wrote was that .
I match with a male ('Fred') on the X chromosome. The paper trail confirms the necessary pattern of inheritance ie from mother to sons and then to daughter(s ), no two males in the chain.
(ie Supposed Female Common ancestor, son, dau, dau, dau , dau, me, and Supposed Female Common ancestor, son, dau, dau, dau, son, dau, Fred )
My son had a 50% chance of inheriting that particular X chromosome If he did then he will also match this match but I can't see how it alters the position. Similarly if I my match was with the testers mother rather than Fred.
(actually I think that I have read there is evidence that the X chromosome doesn't recombine as frequently as the autosomes with the whole chromosome being inherited unchanged in a significant number of cases .This may result in larger segments being retained over more generations which adds another variable )