How do I find out if I was included on my Mothers passport?

[Jessicajane]

My Mother was Born and lived in N. Ireland (1961) before moving to South Africa. She carried a British passport and My Aunt has reason to believe she may have "included" me on her passport when I was Born (1990). I know I am eligible for an Irish passport, and that application process is fairly simple, But I would like to know what the benefits of being included on her passport are? How I would find out if I was? Does it make more sense to apply for a British passport? She passed away in 2002 so I have no one really to answer these questions.
I'm trying to immigrate to the UK in January 2013.

Thanks for your help.

[asim72]

If you were born in SA, then you are automatically a British citizen by descent, as your mother was a " British Citizen otherwise than by descent" at the time of your Birth. If your mother never added your name to her passport, then still you are automatically British as I explained.

You need to provide documentary evidence of your identity and relationship with your mother, and proof of you mother's British citizenship, to obtain a British passport.

You are also an Irish Citizen. You can obtain either or both passports, and can live in UK with either of the passports.

4.2.2.1 Under s.2(1)(a), a person born outside the United
Kingdom on or after 1 January 1983 and before 21 May
2002 is a British citizen at birth if, at the time
of the birth, either parent (see Annex F to Chapter
6) is a British citizen "otherwise than by descent".