fixes #459

src/RadioGroup.js

@@ -6,13 +6,10 @@ const RadioGroup = (props) => {
     const { name, value, children, container,
         childContainer, onChange, ...otherProps } = props;
 
-    const hasOnChange = typeof onChange === 'function';
-    const checked = hasOnChange ? 'checked' : 'defaultChecked';
-
     return React.createElement(container, otherProps,
         React.Children.map(children, child => {
             const clonedChild = React.cloneElement(child, {
-                [checked]: child.props.value === value,
+                checked: child.props.value === value,
                 name,
                 onChange,
                 ...otherProps

src/__tests__/RadioGroup-test.js

@@ -62,7 +62,7 @@ describe('RadioGroup', () => {
 
         for (let i = 0; i < output.props.children.length; i++) {
             const radio = output.props.children[i];
-            expect(radio.props.defaultChecked).toBe(value === radio.props.value);
+            expect(radio.props.checked).toBe(value === radio.props.value);
         }
     });