As described on http://facebook.github.io/react/docs/forms.html, the onChange handler of an input should fire when the checked state changes.  However, it actually fires when the radio button is clicked,

In other words, it fails to fire when a checked radio button is unchecked (by checking a different radio button), and it fires even without a state change when a checked radio button is clicked.

In short, it's missing checked transtions true->false, and it's reporting spurious transitions true->true.

var lastChildren = lastContent != null ? null : lastProps.children;
    var nextChildren = nextContent != null ? null : nextProps.children;
    
    
    var lastHasContentOrHtml = lastContent != null || lastHtml != null;
    var nextHasContentOrHtml = nextContent != null || nextHtml != null;
    if (lastChildren != null && nextChildren == null) {
      this.updateChildren(null, transaction, context);
    } else if (lastHasContentOrHtml && !nextHasContentOrHtml) {
      this.updateTextContent('');
    }
    if (nextContent != null) {
      if (lastContent !== nextContent) {
        this.updateTextContent('' + nextContent);
      }
    } else if (nextHtml != null) {
      if (lastHtml !== nextHtml) {
        this.updateMarkup('' + nextHtml);
      }
    } else if (nextChildren != null) {
      this.updateChildren(nextChildren, transaction, context);
    }
  },
  getNativeNode: function() {
    return getNode(this);
  },
  /**
   * Destroys all event registrations for this instance. Does not remove from
   * the DOM. That must be done by the parent.
   *