diff --git a/src/js/wombJS.tw b/src/js/wombJS.tw
index c61d9a35a0913f9dc618aa6ac4b7a3b6da624fa4..9355f778131a5a1191326cd8431044257e05dff7 100644
--- a/src/js/wombJS.tw
+++ b/src/js/wombJS.tw
@@ -463,12 +463,15 @@ window.BCReserveInit = function()
         slave.womb.forEach(function(ft){
             if (typeof ft.reserved != 'string')
                 ft.reserved = "";
+                if (typeof ft.motherID != 'number'); //setting missing biological mother ID for fetus.
+                    ft.motherID = slave.ID; 
             });
         });
 
     SV.PC.womb.forEach(function(ft){
         if (typeof ft.reserved != 'string')
             ft.reserved = "";
+            ft.motherID = SV.PC.ID; 
         });
 
 }