Hello there
I have been researching John ADAMSON and his family in the 1911 census today and discovered that he and his wife had an extra daughter: their oldest child, Margaret Annie. She appears to have been born a year before they married (Dec quarter 1886, Middlesborough) so immediately I suspected that John or his wife Emma Elizabeth WALDRAM had a previous marriage. Yet, on the 1911 censu, Emma states that she has born eight children and all have survived. There are indeed eight children named on the census. Now, I am beginning to think that she counts Margaret Annie as her own child even though she is not living with the family in 1901 (in fact, I can't find her in 1901) nor in 1891. In 1891, if I have it correct, she is living in Bugthorpe named as Annie, with an eighteen year old Harriet ADAMSON and John ABBOT, Harriet's stepfather and Margaret Annie's grandfather.
Quite a rigmarole and I'm not sure that I have the facts right but it may help you.