It's going to be difficult. Perhaps somebody knows where there is any volume of Wexford records. There are few on IGI or IFHF, and any on FSbeta or FS Pilot only seem to be from civil registration in 1864. You need to look for clues. Check for death records and possible tombstone inscriptions for parents of a townland for place of birth. Religion would also be helpful. This could be on census or christenings of any children. You might also look for migration records. Sorry I couldn't be more helpful. It a case of checking one place after another just to get a single clue. IGI does have a user submission for a 1786 marriage of a Richard Harding in Wexford that could be his father. But there is no spouse name. Peter in Sydney