diff --git a/public/java/src/org/broadinstitute/sting/gatk/walkers/phasing/AllelePair.java b/public/java/src/org/broadinstitute/sting/gatk/walkers/phasing/AllelePair.java
index cb123c868..c629bd313 100644
--- a/public/java/src/org/broadinstitute/sting/gatk/walkers/phasing/AllelePair.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/walkers/phasing/AllelePair.java
@@ -36,7 +36,7 @@ public class AllelePair {
 
     public AllelePair(Genotype gt) {
         if (gt.getPloidy() != 2)
-            throw new ReviewedStingException("AllelePair must have ploidy of 2!");
+            throw new ReviewedStingException("AllelePair must have ploidy of 2! incoming gt was"+gt.toBriefString());
 
         this.top = gt.getAllele(0);
         this.bottom = gt.getAllele(1);