diff --git a/lib/link.js b/lib/link.js
index <HASH>..<HASH> 100644
--- a/lib/link.js
+++ b/lib/link.js
@@ -1,4 +1,4 @@
-import React, { Component, Children } from 'react'
+import React, { Component, Children, PropTypes } from 'react'
 import Router from './router'
 
 export default class Link extends Component {
@@ -7,6 +7,13 @@ export default class Link extends Component {
     this.linkClicked = this.linkClicked.bind(this)
   }
 
+  static propTypes = {
+    children: PropTypes.oneOfType([
+      PropTypes.string,
+      PropTypes.element
+    ]).isRequired
+  }
+
   linkClicked (e) {
     if (e.target.nodeName === 'A' &&
       (e.metaKey || e.ctrlKey || e.shiftKey || (e.nativeEvent && e.nativeEvent.which === 2))) {
Add warning for multiple children in Link (#<I>)

* Add warning for multiple children in Link



* Add space after if



* Use proptype validation