Scotlands National Archives have documents relating to an illegitimate child of Andrew McDouall. The story of this childs conception is immortalised in the songs "Young Peggy" and "Ye Banks and Braes o' Bonie Doon' by Robert Burns, who had met, and was fascinated by the young Peggy. The child, named Helen, was the daughter of Margaret Kennedy, of Daljarroch, who claimed she had secretly married Andrew McDouall, who denied the marriage and paternity. The case was taken to court, and initially won by Margaret Kennedy, however, McDouall appealled the decision, but Margaret "Peggy" Kennedy died in 1796, before the results were given. The appeal overturned the original decision regarding the marriage, but awarded the sum of three thousand pounds to Helen, the child, to be paid by Andrew McDouall, thus confirming his parentage. There are quite a few references to this relationship available on the web particularly concerning the Robert Burns connection.
Margaret Kennedy was my great great aunty, she was the daughter of Robert Kennedy of Daljarroch and Grizel Cathcart (the grandaughter of Sir John Kennedy, 2nd Baronet). I will try to find the reference at NAS and post later.