diff --git a/src/npc/generate/newSlaveIntro.js b/src/npc/generate/newSlaveIntro.js
index 30d38c6059bb2cb6fd0466c6605c9ddb42ad1ea7..29bbe498761a5cf409c1b7f150de8664c5525082 100644
--- a/src/npc/generate/newSlaveIntro.js
+++ b/src/npc/generate/newSlaveIntro.js
@@ -1,9 +1,13 @@
 /**
  * @param {App.Entity.SlaveState} slave
  * @param {App.Entity.SlaveState} [slave2] recruiter slave, if present in the scene
+ * @param {Object} [obj]
+ * @param {boolean} [obj.tankBorn]
+ * @param {string} [obj.momInterest]
+ * @param {string} [obj.dadInterest]
  * @returns {DocumentFragment}
  */
-App.UI.newSlaveIntro = function(slave, slave2, {tankBorn = false, momInterest = null, dadInterest = null} = {}) {
+App.UI.newSlaveIntro = function(slave, slave2, {tankBorn = false, momInterest = "", dadInterest = ""} = {}) {
 	const desc = SlaveTitle(slave);
 	const {title: Master} = getEnunciation(slave);
 	const {