diff --git a/Pv_mod/Population.cpp b/Pv_mod/Population.cpp
index 8e5732432906e51916620d82bb5838b079d10f19..c4b566b76b50cafb8865c71f6caf293bac3daa18 100644
--- a/Pv_mod/Population.cpp
+++ b/Pv_mod/Population.cpp
@@ -172,13 +172,13 @@ void Population::human_step(Params& theta)
 				// males, deficient (hemizygous) 
 
 				HH.G6PD_def = 1;
-				HH.G6PD_activity = gennor(theta.mu_G6PD_def, theta.mu_G6PD_def);
+				HH.G6PD_activity = gennor(theta.mu_G6PD_def, theta.sig_G6PD_def);
 			}
 			else {
 				// males, normal (hemizygous)
 
 				HH.G6PD_def = 0;
-				HH.G6PD_activity = gennor(theta.mu_G6PD_nor, theta.mu_G6PD_nor);
+				HH.G6PD_activity = gennor(theta.mu_G6PD_nor, theta.sig_G6PD_nor);
 			}
 		}
 		else {
@@ -190,7 +190,7 @@ void Population::human_step(Params& theta)
 				// females, deficient (homozygous) 
 
 				HH.G6PD_def = 1;
-				HH.G6PD_activity = gennor(theta.mu_G6PD_def, theta.mu_G6PD_def);
+				HH.G6PD_activity = gennor(theta.mu_G6PD_def, theta.sig_G6PD_def);
 			}
 
 			if ((q_rand > theta.G6PD_prev*theta.G6PD_prev) && (q_rand <= theta.G6PD_prev*theta.G6PD_prev + 2 * theta.G6PD_prev*(1.0 - theta.G6PD_prev)))
@@ -198,7 +198,7 @@ void Population::human_step(Params& theta)
 				// females, deficient (heterozygous) 
 
 				HH.G6PD_def = 2;
-				HH.G6PD_activity = gennor(theta.mu_G6PD_het, theta.mu_G6PD_het);
+				HH.G6PD_activity = gennor(theta.mu_G6PD_het, theta.sig_G6PD_het);
 			}
 
 			if (q_rand > (theta.G6PD_prev*theta.G6PD_prev + 2 * theta.G6PD_prev*(1.0 - theta.G6PD_prev)))
@@ -206,7 +206,7 @@ void Population::human_step(Params& theta)
 				// females, normal (homozygous) 
 
 				HH.G6PD_def = 0;
-				HH.G6PD_activity = gennor(theta.mu_G6PD_nor, theta.mu_G6PD_nor);
+				HH.G6PD_activity = gennor(theta.mu_G6PD_nor, theta.sig_G6PD_nor);
 			}
 		}