[Brown Deer]

...several professional genealogists have traced the same family lineage...

Who are the several professional genealogists who did this?

[Nero Germanicus]

1) ancestry.com genealogists
http://www.ancestry.com/obama
2) Trinty College, Dublin/Eneclann Inc. genealogists & Origins Inc. genealogists in Ireland
http://www.origins.net/help/resarticle-obama.aspx
3) Genealogists working for the Church of Latter Day Saints in Utah
http://p.washingtontimes.com/news/2009/jul/20/obama-hosts-mormon-leader-white-house/