I have a case that really confuses me: my great great grandfather always said he was "of German extraction" and that his father was Henry Richard GIESEN. After 20 years or so of trying to find his birth in 1862, where it should have been, I found a record of him in the 1881 census, Charles Giesen, aged 19, living with his grandmother, Mrs Ann Green, and Mrs Green's other grandchild, one Ada Culling, aged 17. Then I found a record of the birth of one Charles Winchester Green Culling in 1862. I knew his middle name was Winchester, so I ordered the certificate, thinking the Mr Giesen was going to prove to be a stepfather. Almost, but not quite. He was the illegitimate son of Fanny Layton Culling, no father's details given. Ada's birth cert stated she was Ada Anne Green Culling, and further research revealed earlier sons called James Green Culling and Josiah Green Culling. It certainly appeared Fanny was claiming that the children were related to Mrs Ann Green in some way and the only son I knew Mrs Green had was Walter J Green, so I thought he was probably the father of Fanny's four or five illegitimate Green children. Amazement then, when I found in an earlier census (with the help of Rootschatters!) that Mrs Green had an older son - Josiah Green.
Josiah and Fanny never married - in fact Fanny never married anyone as far as I know and she died in her 30s of pthisis - a form of TB.
Charles and Ada were "adopted", still very young, by Josiah's sister Martha, when she married William Henry Giesen - here is where Charles got the story of the "German extraction". After William's tragic accidental death in 1875 Martha sent them to live with Mrs Green, and herself went to live with her twin, Walter. Ada was never very happy apparently, and committed suicide in 1881, two months after the census was taken - by swallowing carbolic acid. She was never talked about by the family, although I recall my grandmother telling me "there was a sister called Ada - but she died." I am never sure how to show Charles' parentage on the family tree. Son of just Fanny, father unknown, as it's unproven? It's only supposition really that Josiah was the father. Natural nephew and adopted son of Martha and William? It's enough to bring on a headache!