Hi,
I have no idea who your Andrew Houston's parents were, but as I am on my own search for Houstons I thought I should contact you. My great great great grandmother was Mary Houston whom I believe was born in Trinity Gask, Perth, Scotland & if so, was the daughter of Peter Houston & Mary Stewart. Again "if" this is the correct family unit, Peter's father was an Andrew Houston who married Helen Miller in Dunning, Perth in 1770. Since Houston (I've seen it spelled Haustin, Austin, Huston, Hewston) is rather unusual, I thought your Andrew & this one might be connected. You never know!
Mary