I mentioned in a reply to you above. The index that is at the Family Page AUTOMATICALLY uses birth as the secondary sort. The POP-UP index - available through various parts of the program (F-2, Menu-person-index, or the index icon next to the mini-tree at the top of the Person tab) will NOT use birth date as a secondary sort. It is helter-skelter. You have to go back to the regular index in the left panel of the Family Tab to see that.
Enhancement Request:
http://community.ancestry.com/feedback.aspx
Enhancement Request:
http://community.ancestry.com/feedback.aspx