diff --git a/acore/enrichment_analysis.py b/acore/enrichment_analysis.py
index 259fe73..f8ac681 100644
--- a/acore/enrichment_analysis.py
+++ b/acore/enrichment_analysis.py
@@ -308,7 +308,8 @@ def run_regulation_enrichment(
             method='fisher',
          )
     """
-    mask_rejected = regulation_data[reject_col]
+    # ? can we remove NA features in that column?
+    mask_rejected = regulation_data[reject_col].astype(bool)
     foreground_list = regulation_data.loc[mask_rejected, identifier].unique()
     background_list = regulation_data.loc[~mask_rejected, identifier].unique()
     foreground_pop = len(foreground_list)
diff --git a/docs/api_examples/enrichment_analysis.py b/docs/api_examples/enrichment_analysis.py
index d7dada2..598a12a 100644
--- a/docs/api_examples/enrichment_analysis.py
+++ b/docs/api_examples/enrichment_analysis.py
@@ -94,6 +94,7 @@
 diff_reg.describe(exclude=["float"])
 
 # %%
+diff_reg["rejected"] = diff_reg["rejected"].astype(bool)  # ! needs to be fixed in anova
 diff_reg.query("rejected == True")
 
 # %% [markdown]