Check if gDay, gMonth, gYear are appropriate as properties of BirthDate and DeathDate
In the XML Schema, the gDay and gMonth datatypes are defined as referring to recurring periods, relative to an arbitrary enclosing period, e.g. the 15th of the month, or the month when annual Thanksgiving celebrations occur (https://www.w3.org/TR/xmlschema11-2/#gDay , https://www.w3.org/TR/xmlschema11-2/#gMonth).
Similarly gYear is relative to the Gregorian calendar.
It seems the xsd date datatype (https://www.w3.org/TR/xmlschema11-2/#date) would be more appropriate to represent the time points associated to concepts like BirthDate and DeathDate.