The quantifiers of P96 by mother and P97 from father

Discussing with the historians  Francesco Beretta and Vincent Alamercery, it is noted that the quantifiers of the property P96 by mother(gave birth) is wrong and the quantifiers of P97 from father (was father for) should be reconsidered taking into acount    cases such as  twins having different fathers. 

It is proposed

(a) the quantifiers of P96 by mother (gave birth) to be changed  from many to one, necessary (1,1:0,1) to many to one, necessary (1,1:0,n)

 (b) to be discussed the possibility of participating more than one fathers in a birth event.  

The P97 from father (was father for) reads in 6.2.2

P97 from father (was father for)

Domain:  E67 Birth
Range:  E21 Person
Quantification: many to many, necessary (1,n:0,n)

Scope note: This property links an E67 Birth event to an E21 Person in the role of biological father.

Note that biological fathers are not seen as necessary participants in the Birth, whereas birth-giving mothers are (see P96 by mother (gave birth)). The Person being born is linked to the Birth with the property P98 brought into life (was born).

This is not intended for use with general natural history material, only people. There is no explicit method for modelling conception and gestation except by using extensions.
A Birth event is normally (but not always) associated with one biological father. 

 Martin , Heraklio 17/11/2016