diff --git a/core/src/main/java/org/elasticsearch/index/query/HasChildQueryBuilder.java b/core/src/main/java/org/elasticsearch/index/query/HasChildQueryBuilder.java
index cb1c59eab01..324552d7b54 100644
--- a/core/src/main/java/org/elasticsearch/index/query/HasChildQueryBuilder.java
+++ b/core/src/main/java/org/elasticsearch/index/query/HasChildQueryBuilder.java
@@ -257,12 +257,7 @@ public class HasChildQueryBuilder extends AbstractQueryBuilder<HasChildQueryBuil
         innerQuery = Queries.filtered(innerQuery, childDocMapper.typeFilter());
 
         final ParentChildIndexFieldData parentChildIndexFieldData = context.getForField(parentFieldMapper.fieldType());
-        int maxChildren = maxChildren();
-        // 0 in pre 2.x p/c impl means unbounded
-        if (maxChildren == 0) {
-            maxChildren = Integer.MAX_VALUE;
-        }
-        return new LateParsingQuery(parentDocMapper.typeFilter(), innerQuery, minChildren(), maxChildren,
+        return new LateParsingQuery(parentDocMapper.typeFilter(), innerQuery, minChildren(), maxChildren(),
                                     parentType, scoreMode, parentChildIndexFieldData, context.getSearchSimilarity());
     }
 
diff --git a/core/src/test/java/org/elasticsearch/search/child/ChildQuerySearchIT.java b/core/src/test/java/org/elasticsearch/search/child/ChildQuerySearchIT.java
index 2fb9366dc14..87d5a00d2a2 100644
--- a/core/src/test/java/org/elasticsearch/search/child/ChildQuerySearchIT.java
+++ b/core/src/test/java/org/elasticsearch/search/child/ChildQuerySearchIT.java
@@ -1561,7 +1561,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         SearchResponse response;
 
         // Score mode = NONE
-        response = minMaxQuery(ScoreMode.None, 0, 0);
+        response = minMaxQuery(ScoreMode.None, 0, null);
 
         assertThat(response.getHits().totalHits(), equalTo(3L));
         assertThat(response.getHits().hits()[0].id(), equalTo("2"));
@@ -1571,7 +1571,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[2].id(), equalTo("4"));
         assertThat(response.getHits().hits()[2].score(), equalTo(1f));
 
-        response = minMaxQuery(ScoreMode.None, 1, 0);
+        response = minMaxQuery(ScoreMode.None, 1, null);
 
         assertThat(response.getHits().totalHits(), equalTo(3L));
         assertThat(response.getHits().hits()[0].id(), equalTo("2"));
@@ -1581,7 +1581,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[2].id(), equalTo("4"));
         assertThat(response.getHits().hits()[2].score(), equalTo(1f));
 
-        response = minMaxQuery(ScoreMode.None, 2, 0);
+        response = minMaxQuery(ScoreMode.None, 2, null);
 
         assertThat(response.getHits().totalHits(), equalTo(2L));
         assertThat(response.getHits().hits()[0].id(), equalTo("3"));
@@ -1589,13 +1589,13 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[1].id(), equalTo("4"));
         assertThat(response.getHits().hits()[1].score(), equalTo(1f));
 
-        response = minMaxQuery(ScoreMode.None, 3, 0);
+        response = minMaxQuery(ScoreMode.None, 3, null);
 
         assertThat(response.getHits().totalHits(), equalTo(1L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
         assertThat(response.getHits().hits()[0].score(), equalTo(1f));
 
-        response = minMaxQuery(ScoreMode.None, 4, 0);
+        response = minMaxQuery(ScoreMode.None, 4, null);
 
         assertThat(response.getHits().totalHits(), equalTo(0L));
 
@@ -1641,7 +1641,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         }
 
         // Score mode = SUM
-        response = minMaxQuery(ScoreMode.Total, 0, 0);
+        response = minMaxQuery(ScoreMode.Total, 0, null);
 
         assertThat(response.getHits().totalHits(), equalTo(3L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
@@ -1651,7 +1651,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[2].id(), equalTo("2"));
         assertThat(response.getHits().hits()[2].score(), equalTo(1f));
 
-        response = minMaxQuery(ScoreMode.Total, 1, 0);
+        response = minMaxQuery(ScoreMode.Total, 1, null);
 
         assertThat(response.getHits().totalHits(), equalTo(3L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
@@ -1661,7 +1661,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[2].id(), equalTo("2"));
         assertThat(response.getHits().hits()[2].score(), equalTo(1f));
 
-        response = minMaxQuery(ScoreMode.Total, 2, 0);
+        response = minMaxQuery(ScoreMode.Total, 2, null);
 
         assertThat(response.getHits().totalHits(), equalTo(2L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
@@ -1669,13 +1669,13 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[1].id(), equalTo("3"));
         assertThat(response.getHits().hits()[1].score(), equalTo(3f));
 
-        response = minMaxQuery(ScoreMode.Total, 3, 0);
+        response = minMaxQuery(ScoreMode.Total, 3, null);
 
         assertThat(response.getHits().totalHits(), equalTo(1L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
         assertThat(response.getHits().hits()[0].score(), equalTo(6f));
 
-        response = minMaxQuery(ScoreMode.Total, 4, 0);
+        response = minMaxQuery(ScoreMode.Total, 4, null);
 
         assertThat(response.getHits().totalHits(), equalTo(0L));
 
@@ -1721,7 +1721,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         }
 
         // Score mode = MAX
-        response = minMaxQuery(ScoreMode.Max, 0, 0);
+        response = minMaxQuery(ScoreMode.Max, 0, null);
 
         assertThat(response.getHits().totalHits(), equalTo(3L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
@@ -1731,7 +1731,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[2].id(), equalTo("2"));
         assertThat(response.getHits().hits()[2].score(), equalTo(1f));
 
-        response = minMaxQuery(ScoreMode.Max, 1, 0);
+        response = minMaxQuery(ScoreMode.Max, 1, null);
 
         assertThat(response.getHits().totalHits(), equalTo(3L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
@@ -1741,7 +1741,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[2].id(), equalTo("2"));
         assertThat(response.getHits().hits()[2].score(), equalTo(1f));
 
-        response = minMaxQuery(ScoreMode.Max, 2, 0);
+        response = minMaxQuery(ScoreMode.Max, 2, null);
 
         assertThat(response.getHits().totalHits(), equalTo(2L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
@@ -1749,13 +1749,13 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[1].id(), equalTo("3"));
         assertThat(response.getHits().hits()[1].score(), equalTo(2f));
 
-        response = minMaxQuery(ScoreMode.Max, 3, 0);
+        response = minMaxQuery(ScoreMode.Max, 3, null);
 
         assertThat(response.getHits().totalHits(), equalTo(1L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
         assertThat(response.getHits().hits()[0].score(), equalTo(3f));
 
-        response = minMaxQuery(ScoreMode.Max, 4, 0);
+        response = minMaxQuery(ScoreMode.Max, 4, null);
 
         assertThat(response.getHits().totalHits(), equalTo(0L));
 
@@ -1801,7 +1801,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         }
 
         // Score mode = AVG
-        response = minMaxQuery(ScoreMode.Avg, 0, 0);
+        response = minMaxQuery(ScoreMode.Avg, 0, null);
 
         assertThat(response.getHits().totalHits(), equalTo(3L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
@@ -1811,7 +1811,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[2].id(), equalTo("2"));
         assertThat(response.getHits().hits()[2].score(), equalTo(1f));
 
-        response = minMaxQuery(ScoreMode.Avg, 1, 0);
+        response = minMaxQuery(ScoreMode.Avg, 1, null);
 
         assertThat(response.getHits().totalHits(), equalTo(3L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
@@ -1821,7 +1821,7 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[2].id(), equalTo("2"));
         assertThat(response.getHits().hits()[2].score(), equalTo(1f));
 
-        response = minMaxQuery(ScoreMode.Avg, 2, 0);
+        response = minMaxQuery(ScoreMode.Avg, 2, null);
 
         assertThat(response.getHits().totalHits(), equalTo(2L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
@@ -1829,13 +1829,13 @@ public class ChildQuerySearchIT extends ESIntegTestCase {
         assertThat(response.getHits().hits()[1].id(), equalTo("3"));
         assertThat(response.getHits().hits()[1].score(), equalTo(1.5f));
 
-        response = minMaxQuery(ScoreMode.Avg, 3, 0);
+        response = minMaxQuery(ScoreMode.Avg, 3, null);
 
         assertThat(response.getHits().totalHits(), equalTo(1L));
         assertThat(response.getHits().hits()[0].id(), equalTo("4"));
         assertThat(response.getHits().hits()[0].score(), equalTo(2f));
 
-        response = minMaxQuery(ScoreMode.Avg, 4, 0);
+        response = minMaxQuery(ScoreMode.Avg, 4, null);
 
         assertThat(response.getHits().totalHits(), equalTo(0L));
 
diff --git a/docs/reference/migration/migrate_5_0/search.asciidoc b/docs/reference/migration/migrate_5_0/search.asciidoc
index 5f1b483cd24..fad75247a23 100644
--- a/docs/reference/migration/migrate_5_0/search.asciidoc
+++ b/docs/reference/migration/migrate_5_0/search.asciidoc
@@ -116,11 +116,11 @@ in favour of `query` and `no_match_query`.
 * The `score_type` parameter to the `nested`, has_child` and `has_parent` queries has been removed in favour of `score_mode`.
   Also, the `total` score mode has been removed in favour of the `sum` mode.
 
-*  When the `max_children` parameter was set to `0` on the `has_child` query
-   then there was no upper limit on how many child documents were allowed to
-   match. Now, `0` really means that zero child documents are allowed. If no
-   upper limit is needed then the `max_children` parameter shouldn't be specified
-   at all.
+* When the `max_children` parameter was set to `0` on the `has_child` query
+  then there was no upper limit on how many child documents were allowed to
+  match. Now, `0` really means that zero child documents are allowed. If no
+  upper limit is needed then the `max_children` parameter shouldn't be specified
+  at all.
 
 
 ==== Top level `filter` parameter