Since there are so many messages on the Group Read board, we like to try to stay on topic if possible. Rachel G and Myretta have answered your question about cousins marrying in the Regency era, which is obviously relevant to MP. ;-) If you'd like to find out about modern practices or those in other countries, you may find some interesting information in the Life and Times archive, which I've linked below. If you search on "cousin", you should find a number of messages related to the subject.