Special License marriage

Question

I've come across two South African marriage certificates recently which have a special license on them. Is there any reason other than age that a special license might be issued? Their ages are 18 and 21 on the one and 19 and 23 on the other.

Answer 1

I think, that in both marriages, one of the spouses was under age of majority

https://en.wikipedia.org/wiki/Marriage_Act,_1961_(South_Africa)

https://en.wikipedia.org/wiki/Children%27s_Act,_2005

Or maybe it was somehow connected with South African apartheid laws?