diff --git a/src/js/generateRelatedSlave.js b/src/js/generateRelatedSlave.js
index 4184291b0ba4f17c83eccbe48715c6fee6d7ca56..7da9340fc75d0036d99fe304e64e6ee9913b8d8d 100644
--- a/src/js/generateRelatedSlave.js
+++ b/src/js/generateRelatedSlave.js
@@ -115,6 +115,9 @@ window.generateRelatedSlave = (function() {
 		if (!V.familyTesting) {
 			slave.relation = "daughter";
 			slave.relationTarget = slave.ID - 1000;
+		} else {
+			slave.mother = slave.genes === "XX" ? slave.ID - 1000 : 0;
+			slave.father = slave.genes !== "XX" ? slave.ID - 1000 : 0;
 		}
 
 		// select age