What are the potential drawbacks of using iframes in PHP for embedding external content?

One potential drawback of using iframes in PHP for embedding external content is that it can make the website vulnerable to security risks such as clickjacking or cross-site scripting attacks. To mitigate these risks, it is recommended to use the `X-Frame-Options` header to control how the content can be embedded in iframes.

<?php
header("X-Frame-Options: SAMEORIGIN");
?>