Just to add more confusion,it is possible to have twins born several weeks apart. My step-brother is proof of that. His twin died having been born very early due to an injury to my step-mum, but she successfully carried her other twin. Sometimes, people don't even know there is another twin still remaining inside and I am sure I have read two conception dates are not unknown, just very , very rare. Plus, my neighbour found twins in her tree, Elizabeth and Mary Jane born 1861. Mary Jane died aged three and the Mum married straight after, but the new husband, a widow, already had a young daughter called Elizabeth, so the poor child had her name swapped to that of her dead twin. She never knew this, but also celebrated the wrong birth date and year all her life. She grew up celebrating her birthday for the date (and year) of her twins death.(so you can imagine, she would have been very big for her age at school !!) The mystery only came to light when no birth certificate could be found for her. Did a wider search, and received a birth certificate , AND the death certificate for the child aged three , so how could she have been my neighbour's gg grandmother? (Even the ladies in the registry office were curious by now.) We discovered the details about the twins , death, and subsequent remarriage and christian name swap , all on the same day- which just happened to be the date poor old Mary Jane had always wrongly celebrated her birthday. I'm sure she was watching over us and having a good laugh as we solved the mystery. I guess genealogy just wasn't on their thoughts way back then! But then, it wouldn't be so much fun, would it? Jo