diff --git a/src/lib.rs b/src/lib.rs
index 6dc7bc7..32f5807 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -380,10 +380,9 @@ impl Agent {
     }
 
     fn cross(&mut self, seed: &Self, cr: usize) {
-        let ratio = rnd!(cr) + 1;
-        let len = self.dna.len();
+        let ratio = self.dna.len() / (rnd!(cr) + 1);
 
-        self.dna[..len / ratio].copy_from_slice(&seed.dna[..len / ratio]);
+        self.dna[..ratio].copy_from_slice(&seed.dna[..ratio]);
     }
 
     fn mutate(&mut self, max: usize) {