diff --git a/gnomad/sample_qc/sex.py b/gnomad/sample_qc/sex.py
index 09ad75108..82ba62d5d 100644
--- a/gnomad/sample_qc/sex.py
+++ b/gnomad/sample_qc/sex.py
@@ -42,14 +42,16 @@ def adjusted_sex_ploidy_expr(
 
     return (
         hl.case(missing_false=True)
+        # Added to reduce the checks by entry.
+        .when(row_idx.in_autosome, gt_expr)
+        .when((row_idx.y_par | row_idx.y_nonpar) & col_idx.xx, hl.missing(hl.tcall))
         .when(~row_idx.in_non_par, gt_expr)
-        .when(col_idx.xx & (row_idx.y_par | row_idx.y_nonpar), hl.null(hl.tcall))
         .when(
-            col_idx.xy & (row_idx.x_nonpar | row_idx.y_nonpar) & gt_expr.is_het(),
+            (row_idx.x_nonpar | row_idx.y_nonpar) & col_idx.xy & gt_expr.is_het(),
             hl.null(hl.tcall),
         )
         .when(
-            col_idx.xy & (row_idx.x_nonpar | row_idx.y_nonpar),
+            (row_idx.x_nonpar | row_idx.y_nonpar) & col_idx.xy,
             hl.call(gt_expr[0], phased=False),
         )
         .default(gt_expr)
diff --git a/gnomad/utils/annotations.py b/gnomad/utils/annotations.py
index 2df5bd7d4..f64b45d4e 100644
--- a/gnomad/utils/annotations.py
+++ b/gnomad/utils/annotations.py
@@ -603,8 +603,8 @@ def create_frequency_bins_expr(
 
 
 def annotate_and_index_source_mt_for_sex_ploidy(
-    locus_expr: hl.expr.LocusExpression = None,
-    karyotype_expr: hl.expr.StringExpression = None,
+    locus_expr: hl.expr.LocusExpression,
+    karyotype_expr: hl.expr.StringExpression,
     xy_karyotype_str: str = "XY",
     xx_karyotype_str: str = "XX",
 ) -> Tuple[hl.expr.StructExpression, hl.expr.StructExpression]:
@@ -640,6 +640,7 @@ def annotate_and_index_source_mt_for_sex_ploidy(
     ).cols()
     row_ht = source_mt.annotate_rows(
         in_non_par=~locus_expr.in_autosome_or_par(),
+        in_autosome=locus_expr.in_autosome(),
         x_nonpar=locus_expr.in_x_nonpar(),
         y_par=locus_expr.in_y_par(),
         y_nonpar=locus_expr.in_y_nonpar(),
diff --git a/gnomad/utils/sparse_mt.py b/gnomad/utils/sparse_mt.py
index a5a59d1a3..ddf6fe1e0 100644
--- a/gnomad/utils/sparse_mt.py
+++ b/gnomad/utils/sparse_mt.py
@@ -990,6 +990,10 @@ def densify_all_reference_sites(
     # Unfilter entries so that entries with no ref block overlap aren't null.
     mt = mt.unfilter_entries()
 
+    # Rekey by requested row key field and drop unused keys.
+    mt = mt.key_rows_by(*row_key_fields)
+    mt = mt.drop(*[k for k in mt_row_key_fields if k not in row_key_fields])
+
     return mt
 
 
@@ -1192,12 +1196,7 @@ def compute_stats_per_ref_site(
         select_fields=row_keep_fields,
         entry_agg_group_membership=entry_agg_group_membership,
     )
-    ht = ht.checkpoint(hl.utils.new_temp_file("agg_stats", "ht"))
-
-    # Drop no longer needed fields
-    current_keys = list(ht.key)
-    ht = ht.key_by(*row_key_fields).select_globals()
-    ht = ht.drop(*[k for k in current_keys if k not in row_key_fields])
+    ht = ht.select_globals().checkpoint(hl.utils.new_temp_file("agg_stats", "ht"))
 
     group_globals = group_membership_ht.index_globals()
     global_expr = {}