child theme function??

hello again..

so how to put the same function code in the child function?? i have this code in my normal theme..

/* Display Facebook and Google Plus button */
function gp_social_share($post_ID){
if(ot_get_option('social_like',1)){
?>
<div id="social-share">
    &nbsp;
    <iframe src="//www.facebook.com/plugins/like.php?href=<?php echo urlencode(get_permalink($post_ID)) ?>&width=450&height=21&colorscheme=light&layout=button_count&action=like&show_faces=false&send=false&appId=498927376861973" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:85px; height:21px;" allowTransparency="true"></iframe>
    &nbsp;
    <div class="g-plusone" data-size="medium"></div>
    <script type="text/javascript">
      window.___gcfg = {lang: 'en-GB'};
      (function() {
        var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true;
        po.src = 'https://apis.google.com/js/plusone.js';
        var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s);
      })();
    </script>
</div>
<?php }
}

and i want to put the same code in child function(+with an extra link) but i get error.