INHERITANCE(FAMILY PROVISION) ACT 1971

"son" and "daughter" respectively, include a male and female child adopted by the deceased under the provisions of any written law relating to the adoption of children for the time being in force and also the son or daughter of the deceased en ventre sa mere at the date of the deceased.
The words en ventre sa mere refers to a child which is still in its mothers womb- an unborn child.From a legal view, the unborn child can also be considered a beneficiary.  Best Regards- Vijay