Hi Peter, Think "Sister by law" in place of "Sister-in-law". The terms in-law and step-... were not fully understood by the masses until quite late - 1870s to 1890s - and did not often appear on the census in those designations until that time. What we know, today, as a step-sister (being the biological child of one of the parents, only) was generally referred to as sister-in-law when in fact the person had been a sister 'by' law owing to the marriage of one of her biological parents to a different spouse than the brother. This scenario also holds true in respect of your man's wife's parents. So, in your case, you will likely find that the sister-in-law had been either, 1. the daughter of your man's mother; 2. the daughter of your man's father; 3. the daughter of your man's wife's mother; or, 4. the daughter of your man's wife's father. Happy hunting and I hope this explanation is clear. Sincerely, Susan D. Young, St. Catharines, Ontario, Canada Chief Executive, Ancestry Solutions www.ancestrysolutions.com County Administrator, Kent OPC www.kent-opc.org ----- Original Message ----- From: "Peter Jones" <peterjones550@btinternet.com> To: <KENT-ENG@rootsweb.com> Sent: Friday, February 05, 2010 5:33 PM Subject: [KENT-ENG] Brother or Sister in Law > Hi List > > > Can someone remind me what the relationship is which would allow a 39 year > old Male to call a 13 year old Female his "Sister in Law"? > > I am puzzled because, as far as I can see, neither the 39 year old nor his > Wife seem to be related to the 13 year old in any way > > Thanks > > Peter Jones > > Studying Trus(s)lers worldwide > > > >