diff --git a/server/routes/pedigree.js b/server/routes/pedigree.js
new file mode 100644
index 0000000..7855ec9
--- /dev/null
+++ b/server/routes/pedigree.js
@@ -0,0 +1,185 @@
+const express = require('express');
+const router = express.Router();
+const { getDatabase } = require('../db/init');
+
+// Helper function to calculate inbreeding coefficient
+function calculateCOI(sireId, damId, generations = 5) {
+  const db = getDatabase();
+  
+  // Get all ancestors for both parents
+  function getAncestors(dogId, currentGen = 0, maxGen = generations) {
+    if (currentGen >= maxGen) return [];
+    
+    const parents = db.prepare(`
+      SELECT p.parent_type, p.parent_id, d.name
+      FROM parents p
+      JOIN dogs d ON p.parent_id = d.id
+      WHERE p.dog_id = ?
+    `).all(dogId);
+    
+    const ancestors = parents.map(p => ({
+      id: p.parent_id,
+      name: p.name,
+      type: p.parent_type,
+      generation: currentGen + 1
+    }));
+    
+    parents.forEach(p => {
+      ancestors.push(...getAncestors(p.parent_id, currentGen + 1, maxGen));
+    });
+    
+    return ancestors;
+  }
+  
+  const sireAncestors = getAncestors(sireId);
+  const damAncestors = getAncestors(damId);
+  
+  // Find common ancestors
+  const commonAncestors = [];
+  sireAncestors.forEach(sireAnc => {
+    damAncestors.forEach(damAnc => {
+      if (sireAnc.id === damAnc.id) {
+        commonAncestors.push({
+          id: sireAnc.id,
+          name: sireAnc.name,
+          sireGen: sireAnc.generation,
+          damGen: damAnc.generation
+        });
+      }
+    });
+  });
+  
+  // Calculate COI using path coefficient method
+  let coi = 0;
+  const processed = new Set();
+  
+  commonAncestors.forEach(anc => {
+    const key = `${anc.id}-${anc.sireGen}-${anc.damGen}`;
+    if (!processed.has(key)) {
+      processed.add(key);
+      const pathLength = anc.sireGen + anc.damGen;
+      coi += Math.pow(0.5, pathLength);
+    }
+  });
+  
+  return {
+    coefficient: Math.round(coi * 10000) / 100, // Percentage with 2 decimals
+    commonAncestors: [...new Map(commonAncestors.map(a => [a.id, a])).values()]
+  };
+}
+
+// GET pedigree tree for a dog
+router.get('/:id', (req, res) => {
+  try {
+    const db = getDatabase();
+    const generations = parseInt(req.query.generations) || 5;
+    
+    function buildTree(dogId, currentGen = 0) {
+      if (currentGen >= generations) return null;
+      
+      const dog = db.prepare('SELECT * FROM dogs WHERE id = ?').get(dogId);
+      if (!dog) return null;
+      
+      dog.photo_urls = dog.photo_urls ? JSON.parse(dog.photo_urls) : [];
+      
+      const parents = db.prepare(`
+        SELECT p.parent_type, p.parent_id
+        FROM parents p
+        WHERE p.dog_id = ?
+      `).all(dogId);
+      
+      const sire = parents.find(p => p.parent_type === 'sire');
+      const dam = parents.find(p => p.parent_type === 'dam');
+      
+      return {
+        ...dog,
+        generation: currentGen,
+        sire: sire ? buildTree(sire.parent_id, currentGen + 1) : null,
+        dam: dam ? buildTree(dam.parent_id, currentGen + 1) : null
+      };
+    }
+    
+    const tree = buildTree(req.params.id);
+    
+    if (!tree) {
+      return res.status(404).json({ error: 'Dog not found' });
+    }
+    
+    res.json(tree);
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
+// GET reverse pedigree (descendants)
+router.get('/:id/descendants', (req, res) => {
+  try {
+    const db = getDatabase();
+    const generations = parseInt(req.query.generations) || 3;
+    
+    function buildDescendantTree(dogId, currentGen = 0) {
+      if (currentGen >= generations) return null;
+      
+      const dog = db.prepare('SELECT * FROM dogs WHERE id = ?').get(dogId);
+      if (!dog) return null;
+      
+      dog.photo_urls = dog.photo_urls ? JSON.parse(dog.photo_urls) : [];
+      
+      const offspring = db.prepare(`
+        SELECT DISTINCT d.id, d.name, d.sex, d.birth_date
+        FROM dogs d
+        JOIN parents p ON d.id = p.dog_id
+        WHERE p.parent_id = ? AND d.is_active = 1
+      `).all(dogId);
+      
+      return {
+        ...dog,
+        generation: currentGen,
+        offspring: offspring.map(child => buildDescendantTree(child.id, currentGen + 1))
+      };
+    }
+    
+    const tree = buildDescendantTree(req.params.id);
+    
+    if (!tree) {
+      return res.status(404).json({ error: 'Dog not found' });
+    }
+    
+    res.json(tree);
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
+// POST calculate COI for a trial pairing
+router.post('/trial-pairing', (req, res) => {
+  try {
+    const { sire_id, dam_id } = req.body;
+    
+    if (!sire_id || !dam_id) {
+      return res.status(400).json({ error: 'Both sire_id and dam_id are required' });
+    }
+    
+    const db = getDatabase();
+    const sire = db.prepare('SELECT * FROM dogs WHERE id = ? AND sex = "male"').get(sire_id);
+    const dam = db.prepare('SELECT * FROM dogs WHERE id = ? AND sex = "female"').get(dam_id);
+    
+    if (!sire || !dam) {
+      return res.status(404).json({ error: 'Invalid sire or dam' });
+    }
+    
+    const result = calculateCOI(sire_id, dam_id);
+    
+    res.json({
+      sire: { id: sire.id, name: sire.name },
+      dam: { id: dam.id, name: dam.name },
+      coi: result.coefficient,
+      commonAncestors: result.commonAncestors,
+      recommendation: result.coefficient < 5 ? 'Low risk' : result.coefficient < 10 ? 'Moderate risk' : 'High risk'
+    });
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
+module.exports = router;
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