United Kingdom - Passport & Nationality - British Citizenship by Double Descent (UKF CBR pre 1983)
Legislation was passed in 2002 to address the unfairness that those born before 1 January 1983 to British mothers could not acquire British Nationality. However, elements of gender discrimination still existed. Those who were born to a British mother who was not born in the UK could not take advantage of the various double descent provisions of the earlier law that were available to those born to a British man. A recent Supreme Court Judgement in the UK has made it clear that it is unlawful for the UK Government to impose a requirement from the past on new applicants for citizenship where it was not lawfully possible for that requirement to be met at the time.
That's the theory, anyway. In practical terms (though there are circumstances where these won't apply), this should benefit those in the following situation:
a) born in a foreign country (which includes South Africa from 31 May 1962, the United States and most European countries);
b) born between 1 January 1949 and 31 December 1982;
c) their maternal grandfather (i.e. their mother's father) was not born in the UK or Northern Ireland.; AND
d) their paternal grandfather (i.e. their father's father) was born in the UK or Northern Ireland.
The final - and key - requirement is that your father must not have had the ability to register you as a British citizen. This would have occured if:
1) your parents were not married at the time of your birth; OR
2 ) your parents were married but the local laws of your country of birth did not recognise the validity of your parent's marriage.