Make the enzygotic data structure exist before trying to add babies to it

1.3/source/RJW_Menstruation/RJW_Menstruation/Hediff_MultiplePregnancy.cs

@@ -726,8 +726,8 @@ namespace RJW_Menstruation
 
         public override void Initialize(Pawn mother, Pawn dad)
         {
-            base.Initialize(mother, dad);
             enzygoticSiblings = new Dictionary<Pawn, Pawn>();
+            base.Initialize(mother, dad);
         }
     }