Dear Wesley, The simplest way to approach this problem is to do autosomal testing of descendents of siblings of Mary's husband, who is presumably the father of the two daughters. If analysis of the data indicates that Sam's son shares the appropriate amount of autosomal DNA with descendents of siblings of Mary's husband, then you know that one of the daughters was the mother of Sam. If analysis of the data indicates that Sam's son doesn't share any significant amounts of autosomal DNA with descendents of siblings of Mary's husband, then you know that Mary may have been the mother of Sam. Determining the parents of ancestors using autosomal DNA testing can be quite challenging, particularly if the ancestor is relatively far back on one's family tree. In this case, 25% of Sam's son's autosomal DNA came from an unknown man. You want to try to figure out which of segments of his DNA came from that man. Testing known cousins on his maternal side would help with chromosome mapping and would bring you closer to determining which portions of his autosomal DNA came from his unknown paternal grandfather. Sam's son's Y chromosome results may well be helpful to you in this quest as well. Sincerely, Tim Janzen -----Original Message----- From: genealogy-dna-bounces@rootsweb.com [mailto:genealogy-dna-bounces@rootsweb.com] On Behalf Of Wesley Johnston via Sent: Thursday, November 19, 2015 4:04 PM To: Genealogy-dna Subject: [DNA] Real Mother - the Mother or adult Daughter? One of our family members has a situation with his father's parents. Mary was married to Joe. They had several children, including several daughters. Joe died. And three years later, when his wife was an un-remarried widow and several of his adult daughters were unmarried and single and living at home, a son Sam was born and raised as Mary's son. This all happened about 100 years ago, and no one now living has actual knowledge of who Sam's parents really were. Sam's birth was never recorded, neither in civil nor church records. Clearly Sam's son (who has DNA tested for all 3 types - y, mt, at) would like to known who Sam's unknown father was. But -- and this is the subject of this post -- he would also like to know who Sam's mother was. Was it really Mary or was it one of her adult daughters? I have been rolling this around in my head -- with no breakthrough. Several of the relatives (all of the generation of Sam's son or more recent) have tested their atDNA (FTDNA Family Finder). Is there some way that we could figure out from how Sam's son matches his cousins whether his father's mother was Mary or one of Mary's daughters?