The nasciturus fiction is the principle where our common law considers a child born alive and conceived before a testator's death to have obtained rights to inherit, from conception.
What rights does a child enjoy if conceived after a testator's death? Such a child is described as a "posthumously procreated child".
Our law is presently unclear about whether a child born of a gamete (sperm in this case), left behind and frozen by a previously deceased father, could inherit. The common law and cases have never had to consider the situation of a child born to a parent that died before conception.
The law does provide for a child born after a testator's
death after natural conception. The wills Act provides:
In the interpretation of a will, unless the context otherwise
indicates any benefit allocated to the children of a person, or to the members
of a class of persons, mentioned in the will shall vest in the children of that
person or those members of the class of persons who are alive at the time of
the devolution of the benefit, or who have already been conceived at that
time and who are later born alive.
The Intestate Succession Act does not deal with inheritance claims by posthumously
procreated child beneficiaries.
See this interesting article on the topic: http://www.saflii.org/za/journals/PER/2018/11.html