I did an ancestry DNA test and was contacted by the daughter of my dad's half sister. I found out that my grandmother had another child, born in the 1940s, which my dad knew nothing about.
She has sent us a copy of her birth certificate with my grandmother's name on it and her adoption certificated which have the date of 1962 on them.
I was wondering whether it would have been possible in 1962 for someone to find out who their birth-mother was and to retrieve the birth certificate.
I want to know how sure I can be that this is really my dad's half sister. I had an 18% DNA match with the half-sister and a 10% DNA match with the daughter.