diff --git a/lshmm/api.py b/lshmm/api.py
index ab76286..e5e2b0b 100644
--- a/lshmm/api.py
+++ b/lshmm/api.py
@@ -108,12 +108,9 @@ def check_inputs(
     if isinstance(prob_recombination, (int, float)):
         prob_recombination = np.zeros(num_sites, dtype=np.float64) + prob_recombination
         prob_recombination[0] = 0.0
-    elif (
-        isinstance(prob_recombination, np.ndarray)
-        and len(prob_recombination) == num_sites
-    ):
-        if prob_recombination[0] != 0:
-            err_msg = "First value in the recombination probability array must be zero."
+    elif isinstance(prob_recombination, np.ndarray):
+        if len(prob_recombination) != num_sites:
+            err_msg = "Recombination probability is an array of unexpected length."
             raise ValueError(err_msg)
     else:
         err_msg = (