20. Meaning of 'person in being'.

A child who is en ventre sa mère at the time of creation of an estate or interest and is afterwards born alive is deemed to be a person in being for the purposes both of the vesting of the estate or interest in him1, and of being a life chosen to form the perpetuity period2. The perpetuity period may, therefore, be extended by a period or periods for gestation, but only in those cases where gestation actually exists