diff --git a/beacon_node/beacon_chain/src/builder.rs b/beacon_node/beacon_chain/src/builder.rs
index 8600d3a7628..ff47c7a2b81 100644
--- a/beacon_node/beacon_chain/src/builder.rs
+++ b/beacon_node/beacon_chain/src/builder.rs
@@ -374,8 +374,13 @@ where
 
         let fc_store = BeaconForkChoiceStore::get_forkchoice_store(store, &genesis);
 
-        let fork_choice = ForkChoice::from_genesis(fc_store, &genesis.beacon_block.message)
-            .map_err(|e| format!("Unable to build initialize ForkChoice: {:?}", e))?;
+        let fork_choice = ForkChoice::from_genesis(
+            fc_store,
+            genesis.beacon_block_root,
+            &genesis.beacon_block.message,
+            &genesis.beacon_state,
+        )
+        .map_err(|e| format!("Unable to build initialize ForkChoice: {:?}", e))?;
 
         self.fork_choice = Some(fork_choice);
         self.genesis_time = Some(genesis.beacon_state.genesis_time);
diff --git a/consensus/fork_choice/src/fork_choice.rs b/consensus/fork_choice/src/fork_choice.rs
index 8be0b328d1f..f6c43ae429a 100644
--- a/consensus/fork_choice/src/fork_choice.rs
+++ b/consensus/fork_choice/src/fork_choice.rs
@@ -240,10 +240,18 @@ where
     /// Instantiates `Self` from the genesis parameters.
     pub fn from_genesis(
         fc_store: T,
+        genesis_block_root: Hash256,
         genesis_block: &BeaconBlock<E>,
+        genesis_state: &BeaconState<E>,
     ) -> Result<Self, Error<T::Error>> {
         let finalized_block_slot = genesis_block.slot;
         let finalized_block_state_root = genesis_block.state_root;
+        let current_epoch_shuffling_id =
+            ShufflingId::new(genesis_block_root, genesis_state, RelativeEpoch::Current)
+                .map_err(Error::BeaconStateError)?;
+        let next_epoch_shuffling_id =
+            ShufflingId::new(genesis_block_root, genesis_state, RelativeEpoch::Next)
+                .map_err(Error::BeaconStateError)?;
 
         let proto_array = ProtoArrayForkChoice::new(
             finalized_block_slot,
@@ -251,6 +259,8 @@ where
             fc_store.justified_checkpoint().epoch,
             fc_store.finalized_checkpoint().epoch,
             fc_store.finalized_checkpoint().root,
+            current_epoch_shuffling_id,
+            next_epoch_shuffling_id,
         )?;
 
         Ok(Self {
diff --git a/consensus/proto_array/src/fork_choice_test_definition.rs b/consensus/proto_array/src/fork_choice_test_definition.rs
index cd38d017c90..9cac0bafb10 100644
--- a/consensus/proto_array/src/fork_choice_test_definition.rs
+++ b/consensus/proto_array/src/fork_choice_test_definition.rs
@@ -55,12 +55,15 @@ pub struct ForkChoiceTestDefinition {
 
 impl ForkChoiceTestDefinition {
     pub fn run(self) {
+        let junk_shuffling_id = ShufflingId::from_components(Epoch::new(0), Hash256::zero());
         let mut fork_choice = ProtoArrayForkChoice::new(
             self.finalized_block_slot,
             Hash256::zero(),
             self.justified_epoch,
             self.finalized_epoch,
             self.finalized_root,
+            junk_shuffling_id.clone(),
+            junk_shuffling_id,
         )
         .expect("should create fork choice struct");
 
diff --git a/consensus/proto_array/src/proto_array_fork_choice.rs b/consensus/proto_array/src/proto_array_fork_choice.rs
index a76cbb3fcbf..e4cf5bbc67b 100644
--- a/consensus/proto_array/src/proto_array_fork_choice.rs
+++ b/consensus/proto_array/src/proto_array_fork_choice.rs
@@ -72,6 +72,8 @@ impl ProtoArrayForkChoice {
         justified_epoch: Epoch,
         finalized_epoch: Epoch,
         finalized_root: Hash256,
+        current_epoch_shuffling_id: ShufflingId,
+        next_epoch_shuffling_id: ShufflingId,
     ) -> Result<Self, String> {
         let mut proto_array = ProtoArray {
             prune_threshold: DEFAULT_PRUNE_THRESHOLD,
@@ -89,12 +91,8 @@ impl ProtoArrayForkChoice {
             // We are using the finalized_root as the target_root, since it always lies on an
             // epoch boundary.
             target_root: finalized_root,
-            // TODO: explain why this is safe.
-            current_epoch_shuffling_id: ShufflingId::from_components(
-                finalized_epoch,
-                finalized_root,
-            ),
-            next_epoch_shuffling_id: ShufflingId::from_components(finalized_epoch, finalized_root),
+            current_epoch_shuffling_id,
+            next_epoch_shuffling_id,
             justified_epoch,
             finalized_epoch,
         };
@@ -351,7 +349,7 @@ mod test_compute_deltas {
         let finalized_desc = Hash256::from_low_u64_be(2);
         let not_finalized_desc = Hash256::from_low_u64_be(3);
         let unknown = Hash256::from_low_u64_be(4);
-        let shuffling_id = ShufflingId::from_components(Epoch::new(0), Hash256::zero());
+        let junk_shuffling_id = ShufflingId::from_components(Epoch::new(0), Hash256::zero());
 
         let mut fc = ProtoArrayForkChoice::new(
             genesis_slot,
@@ -359,6 +357,8 @@ mod test_compute_deltas {
             genesis_epoch,
             genesis_epoch,
             finalized_root,
+            junk_shuffling_id.clone(),
+            junk_shuffling_id.clone(),
         )
         .unwrap();
 
@@ -370,8 +370,8 @@ mod test_compute_deltas {
                 parent_root: Some(finalized_root),
                 state_root,
                 target_root: finalized_root,
-                current_epoch_shuffling_id: shuffling_id.clone(),
-                next_epoch_shuffling_id: shuffling_id.clone(),
+                current_epoch_shuffling_id: junk_shuffling_id.clone(),
+                next_epoch_shuffling_id: junk_shuffling_id.clone(),
                 justified_epoch: genesis_epoch,
                 finalized_epoch: genesis_epoch,
             })
@@ -385,8 +385,8 @@ mod test_compute_deltas {
                 parent_root: None,
                 state_root,
                 target_root: finalized_root,
-                current_epoch_shuffling_id: shuffling_id.clone(),
-                next_epoch_shuffling_id: shuffling_id.clone(),
+                current_epoch_shuffling_id: junk_shuffling_id.clone(),
+                next_epoch_shuffling_id: junk_shuffling_id.clone(),
                 justified_epoch: genesis_epoch,
                 finalized_epoch: genesis_epoch,
             })