Hi, just wanted to ask for clarification regarding family visit visa. I just got my British passport and now plan to sponsor my parents to come to UK for a visit.

Here is the situation:

I am married to a British national.

My birth certificate shows as 'UNKNOWN' on my father's details, due to the fact that my parents aren't married - even until this time.

Obviously my parents don't have a marriage certificate to show themselves as a couple although they are living together since then even until this point of time.

My birth cert only shows the details of my 'mother' but not my father as I would say I was born out of wedlock.

I wanted to know if it's possible that I can sponsor my father to come to the UK for a visit along with my mother.

Do my parents need to get married before I can sponsor them to come in the UK?

or

If there is any other way around for any proof to show that he IS my father.?

Thank you very much....