Will wrote: > So if a father matches on the X to some cousin for say 20cms, the daughter should match *exactly* the same to that cousin > Is that correct? Not quite. The daughter received another X from her mother, and there could easily be segments matching to the cousin on that other X. The reported X matches would be the union of the two sets of matches, i.e., from either X chromosome in the daughter to however many X chromosomes (1 or 2) in the cousin. John Chandler