(In my case Trewhella) I am not really sure.
My brother is a Trewhella (not sure how that worked out but I guess they figured if I am one of them and he is my brother they might as well give him the same surname as mine
- there have been occasions where I have wondered about the sensibility of this plan)
He is actually a good bloke my youngest brother!
Now, he 'was' married (sounds familiar - so was I :
and by 'her' he had two children.
BTW - I think he named his son after old Mathey TREWHELLA of the 'Mermaid of Zennor' story.
His other child was (and still is) a daughter.
And herein lies the problem!
She was born (and I would presume baptised) a Trewhella.
Now she has brought forth a daughter and, at least as far as I am aware
she is not married and there have been no suggestions of marriage. (Well I don't get told absolutely everything!)
So I can see a few options for the Birth Certificate (bearing in mind I was told only an hour after the birth so the child had not yet been named):-
Let us call the girl 'Loveday' for the sake of the excercise.
Loveday TREWHELLA
Loveday (whatever the father's surname is)
Loveday WE HAVE NOT DECIDED BUT WILL LET YOU KNOW WHEN WE DO
And then comes the part we, as family researchers, all love.
The child might be registered as:-
1. TREWHELLA
2. SURNAME OF FATHER
3. 'not telling yet 'cos we don't know'
4. TREWHELLA and then changed later to surname of father
5. surname of father and then no marriage so reverts to mother's M.N.
6.Combination of both names (just like my ex-missus did when she married me :
7. ......................
8. .......................
Use your imagination and let me know of a few other options you may have encountered.
And I bet you all thought a simple question would elicit a simple answer. ;D