Something else to consider, as an argument for a free text field, is the new honorific "Mx" to for a non gender-specific honorific. http://www.gaystarnews.com/article/it%E2%80%99s-going-be-mr-mrs-or-%E2%80%98mx%E2%80%99-brighton-city-goes-trans-friendly180113, http://www.telegraph.co.uk/news/uknews/law-and-order/9634668/Honorifics-could-be-dropped-from-official-letters-by-council.html