Sharon, my earlier message assumed your great grandparents were further back than that. I now realise that you are looking for someone born in the 1920s. Therefore you need to use free BMD rather than GRO index. The question is the same, but free BMD is easier to use.
Dave
Sharon,
I have found Ada J. Gibson in the 1939 Register, she is living 37 Mollart Street, Stoke-on-Trent with Joseph A. Marriott b.17 March 1905 as head of household and property owner, also living there (as a closed record i.e. they were dead by 1991) is J Hollinshead b.21 Sept 1866 (retired corporation labourer). Ada is shown as married with her birthdate given as 19 April 1904. There are 2 more closed records, i.e. still alive in 1991 which could be either 2 children, or her husband and a child. From BMD it looks as though they only had John in 1926 and think Joseph was still living in 1991 so think they are the 2 closed records.