diff --git a/src/js/SlaveState.js b/src/js/SlaveState.js
index 381f9e6605cabbdec98ea673e30f7015c99b242a..0ff663d7f5e4054a057e98037d99afbe4add993f 100644
--- a/src/js/SlaveState.js
+++ b/src/js/SlaveState.js
@@ -2103,6 +2103,10 @@ App.Entity.SlaveState = class SlaveState {
 			/** slave can only ever birth girls */
 			girlsOnly: 0
 		};
+		this.advancedGeneticModifications = {
+			/** Oversized breasts. Increased growth rate, reduced shrink rate. Breasts try to return to oversized state if reduced. */
+			uterineHypersensitivity: 0,
+		};
 		/** Counts various acts slave participated in */
 		this.counter = new App.Entity.SlaveActionsCountersState();
 		/** Values provided by players */